toronto Archives - In Situ Plants Toronto | Green Walls | Live Walls

Calathea rufibarba, a beautiful yet rarely grown species with fuzzy, scalloped leaves which are a deep green above and purple below. Certainly a little more interesting than a Spathiphyllum or other similarly-sized plant, this species garners a good amount of attention. Image © In Situ Plants.

Anthurium superbum, a species with beautiful bullate leaves that thrives in bright indirect light. Image © In Situ Plants.

There are an estimated 400,000 species of plants on earth. While this includes species such as giant marine kelp, leafless parasitic plants, and a slough of other ones not ultimately suitable for indoor cultivation, there are a significant number which will do quite well in an interior setting provided a few basic conditions are met, and certainly more species than are typically seen indoors.

It seems then a disservice to our clients, our own industry and plants in general that most companies seem to prefer to play it safe with the tried-and-true varieties that we’ve all become so accustomed to seeing. They’re about as common as dirt, as the saying goes, and, besides the fact that they (hopefully) have been grown as premium interior specimens and not hastened out the greenhouse door in the fashion of so many of the houseplants sold to the consumer market (the subject of another forthcoming post, I’m sure), there’s not really much to differentiate them from the plants that people are growing on their own at home, or at least that they’re so used to seeing everywhere that they don’t even notice them anymore.

It’s a disservice to clients because, while presumably done with good intentions in order to spare clients the sight of an ailing plant should anything go awry (most of these are very tough to kill [or at least they die slowly and relatively gracefully], and perform fairly predictably), it doesn’t really deliver a tremendous amount of value to the client: certainly they will get the physical benefits of having plants indoors (these benefits were touched on in this post), but the aesthetic and biophilic benefits of plants seem to me somewhat dependent on the plants being engaging and actually noticed, instead of looking like furniture as they so often do. And why have something commonplace when something extraordinary is just as much cost (on their part) and effort (on our part)?

It’s a disservice to our industry for several reasons. As I noted above, to the untrained eye these species, even if they’ve been better grown, look nearly indistinguishable from the ones that can be bought for a pittance at a big box store or wherever; it is challenging to justify the price point for them when someone thinks that they’re the same as the ones they saw for a quarter of the price up the road, even if they get the whole spiel about quality, etc. The other side to this is that many people grow these plants in their home themselves; why, then, would they pay us to do it? Yes, we can do a much better job (hopefully!), but it’s just another aspect we need to justify to the customer. Granted, there are some situations (extreme low light, for example) where only the bulletproof plants will do, but in most situations there is likely something more unique that could be used.

Lastly, it’s a disservice to plants (not that they care): what better way to share a passion for all things green than to try and show the public as much of that world as we can? There’s just so much out there that it seems strange to restrict ourselves to the commonplace when we’re in the business of bringing life into our clients’ spaces; certainly showcasing the extraordinary biodiversity that the plant kingdom has to offer is an effective way of doing just this.

Plants are able to do so much for us, and technology now makes it easier to keep species with particular requirements happy without any additional work (the Calathea above would certainly be trickier without the sub-irrigated planters it’s in; it’s relatively easy to grow so long as it doesn’t go dry). Vertical gardens allow the perfect growing environment for plants so uncommon in cultivation that they don’t even have a common name; the combination of ample water and high humidity makes a huge variety of plants available to the vertical gardener. What a shame then to see so many large, high-profile projects populated by pothos and other common plants when the whole of the tropics could have been the designer’s oyster.

In Situ challenges all in our industry (growers, local wholesalers and interior landscaping firms) to venture off the well-trodden path of Dracaena and Schefflera and step into a world rich in plant species which can grow our industry and the public’s love and appreciation for plants indoors.

If you’re unfamiliar with the chemical reaction above, then you may also be unfamiliar with the fact that life as we typically tend to think of it would not be possible without plants.

Photosynthesis is responsible for the capture of solar energy that in turn powers nearly all life on earth: everything we eat is either plants, or other animals that formerly ate plants (or that ate other animals that ate plants). Plants absorb sunlight and convert it into chemical energy which is stored within the plant for its own uses; we eagerly exploit this by consuming them and thus the sum of the solar energy they’ve stored. Good deal for us, bad deal for the plants (not that they seem to care).

There are not many other ways to capture and metabolize energy in this way, save chemosynthesis (which is why I need to keep referring to ‘almost all life’ above, which, while definitely less dramatic, is more accurate, as there are organisms which are able to capture energy from chemical reactions, most notably in deep-sea communities colonizing hydrothermal vents, and so have no need of sunlight). So plants really are the foundation of nearly all life on the earth.

And not just regarding energy, either. Though a bit more oft-toted, the fact that plants maintain the planet’s oxygen levels is equally prevalent. This does bring up the subject of conservation, but I can save that for another time. I will add in a shameless plug, though, that plants indoors will raise local oxygen levels and just generally improve the air quality indoors. You can read this post for more information if you like: Plants at Work: The Science Behind how Plants Improve Life Indoors.

For anyone interested in the equation who doesn’t understand the chemistry, basically the plant takes 6 molecules of carbon dioxide and 6 of water, and splits these to create free oxygen (which is released by the plant), and a few other goodies which combine with the solar energy captured by the chlorophyll in the plant to create carbohydrates (the C6H1206 in the equation above) which contain that solar energy. Pretty simple, but critical to life on earth.

It’s a little humorous to me that our industry (speaking very broadly here, of course) provides, in a manner of speaking, a product that no one can live without. Maybe that’s why everyone tends to like plants so much: I’ve met many people indifferent to them (and have changed a few minds there), and many more people who love them but can’t seem to stop killing them (and I can only hope I’ve helped a bit there), but have never really met anyone who’s said that they actively dislike plants (except maybe recent victims of poison ivy or the like). Maybe it’s a stretch to assume that we as a species are that aware of the inexorable connection we have with the rest of life, but for whatever reason the biophilic instinct is certainly alive and well.

A photo of the Atlantic Forest of Brazil, a view of which prompted Darwin's words to the right. Image source unknown; retrieved from Projeto Entre Serras.

The cradle of humankind: the plains of Africa. Image © Gossipguy; retrieved from Wikimedia

`…that the naturalist`s journey will go on forever. That it is possible to spend a lifetime in a magellanic voyage around the trunk of a single tree. That as the exploration is pressed, it will engage more of the things close to the human heart and spirit. And if this much is true, it seems possible that the naturalist`s vision is only a specialized product of a biophilic instinct shared by all, that it can be elaborated to benefit more and more people. Humanity is exalted not because we are so far above other living creatures, but because knowing them well elevates the very concept of life.’

E.O. Wilson, from Biophilia

You may have noticed that we reference and tag a word fairly often here at In Situ: biophilia. Biophilia as a concept was developed by the great Edward O. Wilson, biologist, ecologist and prize-winning author, who used it to describe humans’ innate need for affiliation with other living things. From the plants we have kept in our homes since at least the beginning of recorded history, to the out of work domestic animals we still keep around (there aren’t many professional mousers or herders among them these days, at least from an urban perspective- I’m sure there’s still work in the country), to the way we design our cities and parks, human beings have always surrounded ourselves with other organisms. Here’s another (admittedly long) quote by Wilson, who can put it all much more elegantly than I ever could:

‘I have suggested that the urge to affiliate with other forms of life is to some degree innate, hence deserves to be called biophilia. The evidence for the proposition is not strong in a formal scientific sense: the subject has not been studied enough in the scientific manner of hypothesis, deduction, and experimentation to let us be certain about it one way or the other. The biophilic tendency is nevertheless so clearly evinced in daily life and widely distributed as to deserve serious attention. It unfolds in the predictable fantasies and responses of individuals from early childhood onward. It cascades into repetitive patterns of culture across most or all societies, a consistency often noted in the literature of anthropology. These processes appear to be part of the programs of the brain. They are marked by the quickness and decisiveness with which we learn particular things about certain kinds of plants and animals. They are too consistent to be dismissed as the result of purely historical events working on a mental blank slate.’

E.O. Wilson, from Biophilia

So while at the time the book Biophilia was published (1984), there had been no empirical study on the presence of an innate biophilic instinct shared by all of humanity. Since Wilson’s introduction of the hypothesis, many studies have been done that highlight the importance of proximity to nature and other living things to our mental health (see this literature review for a good discussion on some of the studies that have been done: Biophilia: Does Visual Contact with Nature Impact on Health and Well-Being?). Beyond all this, and at the risk of relying on intuition when so many of our human eccentricities are indeed counterintuitive, it just feels correct. At least to me (biased as I might be). Any client I’ve ever spoken with has always pleased with having plants around, and they often comment on how much better a place feels, which seems like mission accomplished and hypothesis confirmed to me.

But how did all this come about? Rooted in our history the habits may be, but the fact that humanity is itself rooted in the natural world is what has caused our deep-seated need to be surrounded by nature. We are the product of a particular habitat, and to this day we still find space in our urban centres for an approximation of it. Think of practically any city park you can imagine. Open grassy areas, with scattered copses of trees; sometimes a pond, fountain or the like. Maybe something somewhat reminiscent of this?

Our species came to be in just such a habitat, and we still seek these same landscapes for comfort, relaxation and meditation. We select our homes in similar ways: perched atop a hill, overlooking water, with a few trees (not too many) here and there describes some of the most sought-after property available (and indeed will often fetch a hefty price).

Turn now to the indoors, where people have been keeping plants for at least as long as we’ve been recording history. All ancient civilizations have depictions of potted plants indoors in the images they created, and sometimes went through great lengths to cultivate plants difficult to grow outside of their native environment (the Romans were building greenhouses even before glass was invented). It is safe to assume that many of these were functional from a medicinal or culinary standpoint, though the Chinese have cultivated ornamental plants indoors for at least three thousand years. Plant mania swept homes and offices in the 1970s, to an extent that has not yet been rivaled (though what those early pioneers of the interior landscape industry would have made of vertical gardening technology!). The interior landscaping industry was born in this era, and has persisted since.

Said industry has often toted the benefits of keeping plants indoors, primarily from a health and employee productivity standpoint (I went through some of the science that these claims are based on here), and some companies have begun to reference the biophilia concept as another selling feature. They are certainly right to do so, but I doubt that many who belong to these organizations have actually read and understood the ideas behind the concept, and are genuinely interested in fostering the sense of interest and wonder in the natural elements we surround ourselves with.

What In Situ is trying to do (and what we would like to encourage the rest of the industry to try to do) is to create more of those moments when nature really takes us in, where time falls away and we are free to explore with our senses the structure of a leaf, say, or the contrasting textures or colours of different plants growing together, to go on Wilson’s ‘magellanic voyage around the trunk of a single tree’. We wish to recreate the forest edge, viewed from our comfortable place amongst the figurative grasslands of our urban interiors, which draws us nearer, showing us glimmers of the mysteries held deeper within. We want to replicate indoors the richness and splendour that has captivated us as a species forever, has inspired countless works of art, and that still, in the lives we live primarily apart from it, holds a special place in our imagination.

‘Among the scenes which are deeply impressed on my mind, none exceed in sublimity the primeval forests undefaced by the hand of man; whether those of Brazil, where the powers of Life are predominant, or those of Tierra del Fuego, where Death and decay prevail. Both are temples filled with the varied productions of the God of Nature: — no one can stand in these solitudes unmoved, and not feel that there is more in man than the mere breath of his body.’

Charles Darwin, from Voyage of the Beagle

By using new and interesting species, and using familiar species in interesting ways, we hope to satisfy the biophilic instinct by completing indoor environments with the engaging natural elements that have been a part of our species’ evolution since time immemorial. When used this way, plants can create a kind of biotic warmth that tempers the sterility of many modern interiors. I don’t advocate turning every indoor space into a jungle (…): rather, the contrast between our manmade constructions and these natural elements are what highlights their presence and what really makes them come to life. The studies I referred to above seem to indicate that having these elements in sight from any area of an indoor space is the optimal placement, and this is the model that many in the industry use when designing their interior landscapes. It`s sound to me, but I feel it’s only effective if the elements are actually visually captivating: this is why we try whenever possible to use plants that people are not usually familiar with, and that have very unique textures or colours, or some other interesting facet to their biology that creates real interest. We seek to foster a true biophilia, through which we can draw inspiration, comfort and knowledge, secure in the surrounds of our earthly cohabitants.

Tillandsia landbeckii, growing where little else will. Image © Eduardo Vergara; image retrieved from Flickr.

Closeup of a Tillandsia sp., showing trichomes. Image © Josef Špaček; retrieved from Botany.cz

Tillandsia biflora in habitat. Image © Jean-Francois Brousseau; retrieved from Flickr

While I don’t wish to discourage anyone from keeping Tillandsia at home, I think that it is important for people to develop a greater understanding of these fascinating plants in order for them to have greater success in their cultivation; they are not as easy of care as most retailers would have you believe, and some species, despite being common in cultivation, are unsuitable (or at best, very challenging) to grow indoors.

The genus Tillandsia is made up of more than 600 species, which is about a fifth of all species in the Bromeliaceae, which includes other favourites such as pineapple. They are distributed, as are nearly all bromeliads, across North, Central and South America (there is one species of Pitcairnea which made it Africa somehow). There is a large variety of form across the genus, as different species have adapted to widely different habitats, from montane rainforests that are some of the wettest places on earth, to arid coastal deserts that receive a scant 3mm of rain annually, at best, and knowledge of where a species originates is of great use when determining how to care for it.

Cultivators of Tillandsia often lump species into two general categories: grey- and green-leaved varieties. This is a pretty good place to start, in terms of their care; the grey-leaved species are typically from more exposed, sunny habitats, and are evolved to make use of the sometimes very little water they receive in these environments, while green-leaved varieties are typically from more shaded, moister habitats. There are exceptions, of course, and so I reiterate that knowing where a species is from will be give you the best chance at success.

The grey colour is due to the leaves’ trichomes, which can perform quite a few functions in plants, but which in this case are designed to capture airborne moisture such as fog, as well as reflect sunlight (up to 45%, apparently). Species will have more or less of these depending on how water-deprived or exposed its habitat is.

The ones more often in cultivation are typically the grey-leaved varieties (though Tillandsia cyanea is definitely another big player, even if it’s typically sold potted along with all the force-flowered Guzmania and Vriesea bromeliads), and I’ll mention a few things about their different habitats below.

Dry Tropical Forest

Many species inhabit dry tropical forest which sees precipitation for only part of the year. Examples of species include T. brachycaulos, T. caput-medusae, and T. xerographica. As epiphytes, these plants are found at different heights on host trees, where there is good air movement (which allows the plants to dry after rainfall) and varying amounts of sunlight depending on where in the tree a particular species is found (and indeed, different species seem to have different preferences for what part of the tree they occupy). These species, because of their requirement for good air movement, are not particularly suitable for most terrariums (despite what you’ve heard), though they do much better in higher humidity than is typically found indoors. A larger terrarium with air movement via a computer fan or the like (see here for some ideas on how to do this, with the understanding that your own endeavors with electricity in moist environments are obviously your own problem) would probably be best, and indeed that’s where I’m having the most success with plants from this type of habitat. Being hung outside under a tree through the summer months (at least here in Toronto) would probably treat them just fine as well.

A note on the seasonality of these habitats: these forests are marked by distinct dry seasons with little to no rain, during which time host trees may drop all their leaves, presumably exposing any harboured epiphytes to more direct sunlight. There doesn’t seem to be much written on coercing these plants to bloom, but in my experience an increase in light can often do the trick, and may well be the trigger for flowering that the plants use in nature.

There are also many Tillandsia species in cultivation which are from disturbingly arid habitats. These are the stiff, very grey-leaved species that are adapted to take what they can get, water-wise: T. tectorum, T. albida and T. edithae are a few examples of species. I say disturbingly arid because these can be some of the driest habitats on earth: the Atacama coastal desert of western South America, for example, has a few weather stations that have NEVER RECEIVED RAIN. Tillandsia species from the Atacama have evolved to take advantage of the coastal fog that rolls in from the ocean, allowing the plants to capture airborne moisture. Some xeric species inhabit high elevations in the Andes, and take advantage of the clouds that float through their habitats.

These species are much more tolerant of dry air, direct sunlight and restricted moisture, but the converse to this is that they need a lot of sun and also cannot be kept too moist. South-facing windows (or, optimally, a solarium or greenhouse) are probably best in the case of these plants, and they are definitely not suited for most terrariums.

A note here on watering Tillandsia: these plants use CAM (Crassulacean acid metabolism) photosynthesis, which is really neat and interesting and worth talking about at length, but which for our purposes here means that they open their stomata to absorb carbon dioxide at night rather than during the day as do most other plants. Wetting the plants before nightfall can inhibit this gas exchange and in effect suffocate the plants. The xeric plants, at least, receive moisture in their native habitat before dawn, allowing them to absorb carbon dioxide and then liquid water before the demands of the desert day begin. I don’t advocate waking up at 4:00 a.m. for any reason (though maniacal plant care is, in my opinion, a better reason than most), but watering your Tillandsia in the morning is probably best practice. And water them well: aside from the really effective water-catchers like T. tectorum, the oft-recommended misting with a spray bottle isn’t going to do much for the plant: give it a good soaking with a watering can or a quick dunk in a bucket.

Moist Habitats

Though not as common as the ones you find piled haphazardly in a basket at your local florist or garden centre (can you tell that gets on my nerves?), these are my personal favourites. Even T. cyanea, which is pretty boring as far as these go, foliage-wise, is an easy to grow species that does well in a pot. These species are, as far as I know, strictly epiphytic, and inhabit some of the wettest habitats on earth. The aforementioned T. cyanea, T. flabellata and T. biflora are three that can be found with a little digging (some more than others).

Conditions should be moist and humid, but with very good air movement, and lighting can be lower than for species from the previous two habitats I mentioned, so if you’ve been losing plants due to a combination of low light and excessive moisture, you might want to try one of these. T. cyanea is a tough plant, but T. biflora, in my experience, is not, and best results will be had in a greenhouse or large terrarium with good air circulation.

There are obviously gradients to these habitats I’ve mentioned here, and research into what species you have will give you the best idea of how to care for it. A little experimentation never hurts either (OK, sometimes it does), and you may find that some species are quite forgiving in cultivation. The lesson here is that, at least nine times out of ten, your local purveyor of Tillandsia hasn’t the slightest idea of how to keep them alive over the long term (you can even buy them in furniture stores now, apparently: I saw a bunch of mounted ones piled crudely on top of each other in a West Elm store here in town), so you should do your homework if you’d like to have success with this interesting group of plants.

Sporophyte fronds of what I`m presuming is Adiantum peruvianum, doing their thing in one of In Situ's vertical gardens. Image © In Situ Plants.

Just a short one here, but I’m pleased to report that the little gametophytes I wrote about back in June have started to produce their first fronds, AKA sporophytes (being the part of the plant that eventually produces the spore which gifted us with the gametophytes in the first place). Again, I can only presume that these are Adiantum peruvianum, as this is the only fern species in this garden, but there are a lot of other ferns here at the lab (to say nothing of the effectiveness of travel by spore; these ferns really could be from anywhere), and so I’m still not 100%. (And there’s actually a terrarium in another room of the building that appears to be growing something similar, so the plot could still thicken here.)

They’re pretty cute, though, either way. As soon as we start to see more mature foliage on these plants I’ll update again with a more conclusive ID. The plants pictured here are way up at the top of the wall, and should produce a nice (albeit unplanned) cascading effect once they get going (again, presuming they’re even A. peruvianum).

We, as an industry, nearly always tote the benefits of interior plants, and I’m here to tell you that it’s not just bullshit: there are measurable effects in the way people think, behave and feel when they are in an environment that contains plants versus one that does not, and plants actually are able to clean the air we breathe.

Instead of doing what everyone else does, which is usually just to concisely (we all know that’s my strong suit, ha ha) list the same key points, I’ve done the legwork and actually rustled up a few of the papers from which said points were drawn from, and will point you to them so that you can read for yourself the results of some of the various studies that have been conducted over time.

By all means be skeptical, and don’t take our word for it: we’re very few of us scientists in this industry, but there has been real scientific work done which really confirms what we’ve been saying all along: that plants indoors have a direct effect on things like employee productivity, reduction of airborne pollutants, and combating stress and fatigue.

Cleaning the Air

So for starters, do plants actually clean the air? It would be a boring blog post indeed if I said no, and here are a few papers which highlight some of the work that different plants (and their associated colonies of soil-dwelling microorganisms) do to remove harmful chemicals from the interior atmosphere. What I’m not going to do is tote the old NASA study that gets thrown around so often: you can look that up for yourself, but Dr. Wolverton (and others) have continued to do good research into this phenomenon since the first study was published in the 80’s.

Plants and Soil Microorganisms: Removal of Formaldehyde, Xylene, and Ammonia from the Indoor Environment

This study found that quite a few plant species, notably Boston ferns, chrysanthemums, and dwarf date palms, were able to remove appreciable amounts of these chemicals from the air inside sealed chambers. Based on prior research into indoor air pollutants by the EPA, the authors calculated that an average-sized office constructed of typical building materials would contain 3916 µg (micrograms) of formaldehyde (to use the most sinister example in the paper). A single Boston ferns was shown to remove 1863 µg of this formaldehyde- per hour! The mums and palms were not far behind, and there was a decent list of other plants which were also quite effective at removing formaldehyde from the air.

Figure 1 from the study linked above, showing formaldehyde
concentrations being removed by a Boston fern. — Figure 1 from the study linked above, showing formaldehyde concentrations being removed by a Boston fern.

The other part of the study looked at the microorganisms which colonize the rhizosphere (the area immediately surrounding plants’ roots), and the role they play in the removal of these chemicals. They found that unsterilized soil was able to remove formaldehyde from the air while sterilized soil was not, and that soil containing a plant was more effective still. They found that different types of bacteria had an effect on how much formaldehyde was removed, and the data indicated that different plants harbour different types of soil bacteria. Check out the paper for yourself: I’ve linked to it above.

Purification Ability of Interior Plant for Removing of Indoor-Air Polluting Chemicals Using a Tin Oxide Gas Sensor (sic)

This study performed similar experiments to the one above (you can read it yourself for the full details), with a slightly different method. Their results were similar: plants and their associated bacterial communities removed airborne pollutants quite effectively from the atmosphere. One point of note is that temperature and light had a large effect on the experimental results, suggesting that plants are more effectively cleaning the air when they are actively growing (see the portion in the discussion on uptake of gases through stomata if you like), which really bolsters the case for optimizing plant health in the interior landscaping in order to maximize this beneficial effect.

Improving Employee Productivity

This is a claim that is often used because it seems to infer a real economic benefit to the client. I’m inclined to agree with the science, and I can see that this certainly makes interior landscaping more marketable, but it almost feels like a bribe: surely plants can be desirable of their own merit, and surely the effect they have on people should not be measured in terms of productivity but of general mental and physical health? Do clients actually purchase plants to get more out of their staff? At any rate, the effect has been measured in the following papers (and I’m sure there are more); let’s call it here just an added bonus to the addition of plants to the workplace.

Interior Plants May Improve Worker Productivity and Reduce Stress in a Windowless Environment

This is one of the commonly cited ones, in which the authors noted a 12% increase in productivity (measured as reaction time to a computer task). I’m not sure that this is really a rock-solid study, and I wish I could have found another paper which replicated the experiment, but it’s here, for what it’s worth. One more interesting point in the study is the result on the blood pressure of the participants, which measured significantly lower during and after completing a computer-based productivity task in participants in a room with plants versus that of those in a room without.

Effect of Ornamental Foliage Plants on Visual Fatigue Caused by Visual Display Terminal Operation

I’m hoping that someone’s Japanese is better than mine and they might comment on this paper, but based on the English abstract and the figures in the results, these researchers found that viewing plants while performing tasks on a visual display terminal (presumably a computer screen of some sort) resulted in reduced visual fatigue when measured as critical flicker fusion frequency (a somewhat complicated phenomenon that you can look up on your own). I can’t comment much on this one, as I can’t even read it, but the numbers are there.

Plants Enhance Productivity in Case of Creative Work

This is more of a press release than an actual paper, I think, but it highlights the results of an experiment carried out by researchers in The Netherlands, which found that, while no improvements to productivity tasks were noted, there was a marked improvement in performance of creative tasks. These improvements were even more dramatic with test subjects with self-reported stress or exhaustion (the study used students as their guinea pigs)

In Situ Plants interior landscapes, vertical gardens, and other plant installations in Toronto — Figure 2 from the productivity paper above, showing the number of correct associations by students who reported a high level of physical exhaustion.

General Health and Wellbeing

This is probably the most important one for me, because it has much to do with the concept of biophilia, which I will be addressing soon (likely at great length), and which is tied very closely to In Situ’s raison d’être. We believe that humans have an innate subconscious need for proximity to natural elements, and keeping plants indoors proves to be a noteworthy way of satisfying this in our modern urban settings.

General mental health seems a difficult thing to quantify, but the works below are able to convey a few measured benefits to having plants around us while spending, as we typically do, the majority of our time indoors.

Stress Recovery during Exposure to Natural and Urban Environments

This almost creepy lab study measured several parameters (heart rate, muscle tension, etc.) during and after showing the poor participants videos of people getting into violent industrial accidents, followed by a video of either a fast-moving stream, a wooded area, or varying degrees of busy vehicle or foot traffic. The results clearly showed that the wooded scene was very effective in recovery from the stress indicated in the physical tests.

The self-report from the participants also indicates that the nature scene was the most positively affective by far, and best able to reduce anger, aggression and sadness.

Greening the Great Indoors for Human Health and Wellbeing

This extensive study looked at various aspects of how keeping plants indoors relates to human well-being, from mental and physical standpoints. In section 5, the authors had their subjects complete Profile of Mood States questionnaires (apparently a widely accepted method for measuring different psychological states) before and after the placement of varying numbers of plants in their workspaces for a period of three months. The questionnaires covered such feelings as tension/anxiety, fatigue, and confusion.

The data shows that plants did in fact affect these parameters, and that the control group with no plants scored even worse on the questionnaire than it initially had done, while the subjects with plants saw their scores improve markedly.

The Role of Nature in the Context of the Workplace

This is also mostly a literature review, and includes quite a few statistics from other authors’ papers (which is why I’ve included it here), but the author points to two of her own studies, and I’d like to summarize here the gist of the second one: in a survey rating employee satisfaction, the availability of a view out of doors was considered far more valuable and restorative if it contained natural elements, and became even more so the more natural elements could be seen. Further to this, respondents with clear outside views to natural elements reported feeling more positive about their work in general. From the above:

“These results point to the range of impacts that a view of nature can affect. Those with a view of nature felt less frustrated and more patient, found their job more challenging, expressed greater enthusiasm for it, and reported higher life satisfaction as well as overall health.”

Pretty interesting stuff, I think. It will be interesting to stay on top of the science and see what further studies come from this quarter. If anyone has any further information on this they want to share (for or against, of course, though I bet you’d be hard pressed to find a study against plants in buildings), be sure to include it in the comments.

Dryadella cristata, grown on a cork mount: no soil, no problem. Photo © In Situ Plants

Seemania purpurascens, one of the many fuzzy-leaved gesneriads that doesn't particularly appreciate cold water on their leaves. Photo © In Situ Plants

Ways to Tell if a Plant Needs Water (Or Not)

We obviously would prefer not to greatly disturb a plant`s soil every time we water by performing a squeeze test to see how much water is in the soil (see here), but we definitely want a clear idea of how moist the soil is. Below are a few ways to find out.

One effective way is to stick your finger in it. For real: you will be able to feel if the soil is dry or moist, and the sense will become sharper with practice and experience, to the point where you will be able to tell whether it’s quite moist, just moist, etc. The only issue is that you can only measure the soil to the depth of your finger (unless you’re working in bigger containers, in which case go on and get your arm in there). You’ll also get dirt under your nails this way. There are soil moisture meters you can buy that likely do a better job than your own finger (they’re longer, for one thing), but I can’t really comment on them, having never used them myself.

Soils tend to dry from the top down, and even if it’s bone dry on the surface there may be an appreciable amount of water lower in the container, particularly if it is large or if the soil is of poor quality. Keep this in mind when you’re checking your plants. (This would probably be a good place to emphasize the value of good quality soil: the stuff you buy in the little bags at the hardware store or garden centre is not worth the bag you buy it in, in my own humble opinion. I will likely write another post on this, as it’s certainly worth one, but suffice it to say for now that you will have better luck with plants indoors grown in something described as a ‘growing medium’ instead of a ‘potting soil’. The differences in their properties make a large difference in how much water they hold and how available it is to the plants.)

Another way to gauge the amount of water in the soil is to lift the pot (or tip it, in the case of larger containers). Moist soil weighs considerably more than dry soil: fill one pot with moist soil and another with bone dry soil and try it for yourself. The difference is dramatic, and as you get into the habit of lifting your plants you will really get a feel for how much water there is in the soil. This technique works especially well with plants still in their plastic grower’s pots (and indeed, I first learned this technique in a greenhouse). Heavy ceramic containers make the method a little trickier, but not impossible.

Sometimes plants will let you know if they are thirsty by actually looking thirsty. This is called flagging in some circles, and it’s a fitting word: a flagging plant can stand out like a sore thumb to the trained eye amidst an acre of its counterparts. It can be a subtle paling of colour or slight drooping (or raising, in some cases- Calathea comes to mind) of the leaves. Though it`s probably best to water the plant before it gets to this point, at least you can (hopefully) take measures before there is extensive damage to the plant.

Which is the next point. There are two points beyond this: a temporary wilting point and a permanent wilting point, which are quite self-explanatory. There are quite a few plants that lack a temporary wilting point, though, and if they go too dry but once they’re done for. Other plants will recover but never be the same again, while yet others can completely collapse and look as dead as you like, but give them a drink and they bounce right back, without any apparent damage.Some don’t seem to even have a wilting point: they just soldier on, bone dry, as the weeks go by. (But even they get there, eventually.)

Plants damaged by too much or too little water can display symptoms such as yellowing/browning/loss of lower leaves, and wilting (though none of these are exclusive to water management alone- nutritional and other disorders can produce similar effects). As we’ve seen, the effect of too much or too little water is the same, and so the symptoms are similar. What will likely be different between an overwatered and underwatered plant is the soil moisture: if a plant looks dry but the soil is moist, you will know (unless you just watered it, of course) that the plant is too moist and needs to dry down. These symptoms above ground are a reflection of what’s happening in the root zone: if there has been extensive damage to the roots they may not be able to take up enough water for the plant to be able to support the top growth.

How To Water

I’d like to include a few things to think about when it comes time to actually water your plants. It isn’t, unfortunately (even after having waded through the preceding paragraphs), as simple as just dumping the right amount of water into the pot.

It helps to have at least a rough idea of how much water you’re applying to give you a good frame of reference for whether that amount is too much/not enough/just right. I don’t mean breaking out the graduated cylinder, but knowing how much your watering can can hold, for example, will help give you a good enough idea of how much you’re actually giving the plant, so you can adjust or keep steady the amount that’s best for it.

And I know I spent a whole long while talking about the value of a schedule, but if you check your plant on the given day and it doesn’t seem like it needs any water, by all means skip it. You may need to keep an eye as you get closer to next week’s watering to make sure it hasn’t dried out too much, but if the plant doesn’t need a drink then it shouldn’t get one. Fairly common sense, but this is the danger everyone warns of when they tell you not to get on a schedule in the first place.

It’s not always possible, but using a watering can with a breaker (the round bit that attaches to the spout with the little holes in it) is best, in my books: it slows the flow of water so that you can be more accurate in the amount you’re applying, and it waters across the entire surface of the soil, which is helpful if the surface has dried faster than it has further down in the pot. A good soil will move moisture throughout itself to a point, but soil will be more easily and evenly moistened if water is applied across the entire surface, so even without a breaker I try and apply the water somewhat evenly around the pot.

Use (at least) room temperature water: this is really important if you want your plants to actually grow. I haven’t actually experienced damage to plants through irrigating with cold water (maybe because I don’t do it), but I have heard and would be inclined to believe that it is a risk, particularly with cold-sensitive plants like Aglaonema. (I looked around online for papers or some credible source, but couldn’t find anything). What I do know for a fact is that water temperature is used in commercial greenhouses to control certain crops, with applications of cool or cold water controlling height and rate of growth in order to produce a crop that is finished on time, and at the standard size (think Easter lilies).

Watering from overhead is great if you can swing it: it helps to clean the leaves, and I feel like that’s how the plant would typically receive water in nature. Without the type of air movement experienced out of doors, though (to say nothing of the impracticality of it indoors, too), overhead watering can cause water to collect and remain in the crowns or axils of plants without evaporating away, where pathogens can take up residence and cause problems; crown rot of Phalaenopsis orchids is a big one that comes up a lot. Again, use warmer water, and water early in the day so that the foliage has a chance to dry before it cools down in the evening in order to keep these diseases from establishing themselves.

Well, there you have it. I guess in closing I should probably apologize for making such a simple thing so complicated, but as I mentioned at the beginning, watering is probably the thing that most people have a tough time getting right. I hope that the info I’ve included here is of use in your growing endeavors, and please let me know in the comments if there’s anything you feel I missed or that needs clarification. And I’d like to thank Albert Grimm and Bill MacDonald for first complicating the subject for me: many (if not most) of the concepts you’ve read here came from them.

Utricularia australis, which prefers to grow on the wetter side of wet. Image © Josef Hlasek; retrieved from his website

How Much Water?

Once a schedule (see the last post) is in place that allows you to maintain better constancy in your soil moisture, you can now tailor the amount of water you apply to different plant species. There is no plant I know of that does not appreciate water, unless it is in dormancy. The issue is with the amount of water, and thus the amount of air, that is in the soil at any given time. Most cacti, for example, are evolved for long periods of drought, but this doesn’t mean that this is their preference. So often certain plants are described as ‘needing to dry out between watering’, but the truth is that this is not the case: rather, the plant needs to be prevented from ever becoming too moist for too long. Maintaining a very light but consistent level of soil moisture will allow xerophytic plants like cacti to maximize their growth without causing damage to the roots. This requires something of a steady hand in order to not give your plants too much water, and adapting your soil for different species can help a lot to get things perfect (in the case of cacti and other succulent species, I recommend adding something with a large particle size that improves the aeration porosity of the soil). It is worth noting, though, that with careful watering alone, you should be able to keep widely different species in a standard peat/perlite mix.

Knowing which species you are caring for is the first part of knowing how much water a given plant will need. There are countless resources online and elsewhere that recommend care for the majority of species in circulation. If you’re more inclined to nerdiness like me, you’ll also probably look into where the plant originates in order to learn more about its natural habitat, and take cues from this towards the plant’s care. (I will write more on this at some point; I promise.) All this, though, needs to be tempered with your own experience of the plant and how it grows in your environment, and this requires that you pay attention to what your plants are doing, and how their environment changes throughout the year. Some species are known to rest a little through the winter, for instance, and typically these do not require much moisture at that time. Conversely, the air generally becomes much drier indoors during the winter, when we run our furnaces, which may contribute to the plants’ increased respiration and thus need for additional water. Your growing situation is unique, and it is up to you to find what works best.

Some plants prefer a moist soil, and yet do not take up too much of the water, so after obtaining the correct level of moisture, one can apply small amounts to compensate for the plant’s uptake and any loss through evaporation. One the other hand, some plants which prefer moist soil use a tremendous amount of the available water, and so will need to be watered heavily on the regular. Plants receiving more light will use more water than those in shadier spots (and will require more feeding, but this is best left for another time). Larger plants will obviously use more water than smaller ones, though larger plants are often more drought-tolerant than smaller ones.

A quick note on watering until water flows from the bottom of the pot: unless your water is of very poor quality or you are feeding large amounts of fertilizer, this practice is not really necessary. It is a good way to ensure that your soil becomes evenly moist (read saturated), and it is definitely helpful to have drainage in the event that you do overwater, but it is also a waste of water. In our industry we keep plants for many, many years in containers which do not drain, and they fare quite well. Another aspect to this is that if soil is completely dry, often the applied water will travel straight through it and out the bottom of the pot without wetting anything along the way, which can give a false sense of accomplishment if all we`re looking for is water pouring out from the bottom. If your soil is already a tiny bit moist, simply water carefully (read slowly) until you bring the soil to where you want it, moisture-wise, and you won’t need to waste any water.

Quantifying (sort of) Soil Moisture

So I just spent a whole bunch of paragraphs explaining that different plants prefer different levels of soil moisture, often at different times. But what does barely moist or nearly wet actually look and feel like?

Enter the squeeze test. In most quality peat-based media (not the off-the-shelf stuff), the soil will dry to a conspicuous pale tan colour. If the soil is completely dry, take a handful and squeeze it and it will not hold together. A slightly moist soil will be slightly darker and will mostly hold its shape if you squeeze it as above. Moderately moist will be darker still, and should hold together and even release a tiny bit of moisture if squeezed. Moist and saturated soil will be as dark as the soil can get, with some and quite a bit of water, respectively, released upon squeezing.

This squeeze test is a good way to familiarize yourself with how much water is in the soil in relation to its appearance. Once you get a feel for it (ha ha) you will be better able to eyeball the moisture level of the soil more accurately, though relying on appearance alone can sometimes be deceiving (more on this in the third part).

If a plant wants to stay moist but not wet (and many do, but please don`t accept the care instructions that come with purchased plants as gospel, for there are quite a few variables I’ve already mentioned [and more that I haven`t] that can affect how much water a plant uses), keeping it between moderately moist and moist will likely keep it happy. Keeping a soil barely moist, as I mentioned above, is a great way to optimize the soil environment for succulents or similar plants. And then there’s all of the in-between.

You will need to make your best judgement as you work with soil moisture levels based on your growing environment and the species you’re working with. Don’t be afraid to experiment, but make your changes incremental as you pay close attention to the plant in order to draw useful conclusions and avoid issues.

One more thing I think I should note before I leave off: you’ll notice that I keep (almost exhaustingly, probably) using the word soil, and I should clarify that when I say this I am referring to whatever you’ve got your plants growing in (which I hope is a high-quality peat-based growing medium), and not that heavy mineral stuff from the back yard. These high-quality growing media are referred to as soilless mixes for the fact that they do not actually contain proper soil, but for our purposes here the term soil will be used (in part because it’s shorter and I seem to be typing it an awful lot).

I’m going to follow this post with one on Ways to Tell if a Plant Needs Water next week.

A photo of a sopping wet rainforest which I've put here instead of a boring stock image of someone watering a houseplant. Bosque Protector Los Cedros, Ecuador. Image © In Situ Plants.

The Moisture Release Curve, showing how water is available (or not) to plants. Image © Dr. Heiner Lieth; Retrieved from his page on the University of Caifornia website.

Watering is perhaps the greatest challenge people face when keeping plants indoors: getting it wrong can prove disastrous for many species, and it can be frustrating to lose a plant. As professionals, we are often asked how much water a plant needs, how often it needs it, and how to tell if it’s too much or too little.

I can’t give you all the answers: every plant is different, as is every interior environment, and both plants and their environment can change quite often. I can, however, outline (in a long-winded, but hopefully informative way) a few principles and techniques to help you answer these questions for yourself so that you can have greater success keeping plants indoors. This is Watering 102 because there are some more complex ideas here than are covered by other watering articles online for those that really want to nerd out about it.

After having finished this first bit, I’ve decided to release this guide in three parts, as it’s become almost absurdly long and you’ll probably want a break in between. I apologize in advance for not having kept it all more concise; please let me know in the comments if anything needs clarification. Today’s tome of a post covers irrigation frequencies and the moisture release curve of growing media. Don’t be scared.

How Often Should I Water?

Irrigation frequency is a something of a complicated subject, as there are many factors at play. Some plants need more or less water than others, and these needs can change throughout the year. What follows are a few considerations to keep in mind as you decide for yourself how often to water your plants.

From an industry standpoint, many professional companies, in the interest of reducing labour spent on maintenance, visit their plants every two or even three weeks. (There are some that go even longer, but they either do a horrible job or else make use of sub-irrigation technologies to ensure plants have access to water in the interim.) At In Situ, we typically visit our plants once a week. (Just sayin’).

The reasons for doing this are many, but an important one is to ensure that our plants make the best use of the water that is applied. We are typically maintaining larger plants than those often found in homes, but unless your plants are very small (4” pots or smaller, say), your space is especially warm or dry or the plants are in direct sun, weekly is probably a safe bet, or at least a good place to start when creating a schedule. Pick a day where you know you’ll have the time, and stick with it.

Note that when I said above that we water once a week (typically) in order to aid the plants in making the best use of the water we apply, I did not say that we necessarily apply more water than if we were to water every two weeks. In fact, the chances are that we apply less water over a two week period in two doses than we would do in a single dose. This is because soil that is still slightly moist can reabsorb water better than one that is bone dry. Peat moss (the main ingredient in most growing media), when dry, is hydrophobic, and actually repels water: we’ve probably all tried to water a plant and had the water glance off the soil and fly out of the pot and onto the floor, right? Never allowing the soil to completely dry allows one to apply only a minimum of water in order to bring the soil to the desired level of moisture, without having to rewet all the peat every time, which usually leaves it saturated, which can be dangerous.

Other sources may tell you that watering on a schedule can be bad for plants, and that the best thing is to ‘water when the plant needs it’. Watering exactly when the plant needs it is great if we have little else to do but hover over our plants with a watering can all day. Watering on a schedule can be bad if you are just blindly applying the same amount of water every week, say.

Watering at regular intervals, though, can allow one to monitor the plants and to see what the effect of the last watering has been. For instance, if a week has passed and you check your soil to find that it is still very moist, chances are that you probably applied a bit too much water the last week, and you can ease up a little going forward. Likewise, if you discover a very dry soil (and hopefully not a wilted plant!), you can probably begin applying a little more water every week. Plants’ needs can change from week to week as well, due to the weather, whether the plant is flowering, etc., and so we need to take this into account when we do water.

Most potted plants (as opposed to those in hydroponics or the like), cannot take up water from saturated soils, because the extra water has displaced all the gases in the soil, primarily oxygen. This interferes with the normal growth of the plant (part of which involves taking up the water from the soil) and also causes roots to die, having been, in effect, suffocated.

Plants that are watered infrequently typically need a large amount of water applied to ensure that they do not go too dry before they are watered again. The consequence of this is that there is a period immediately after the plant is watered where not only is it not using the water (because it is unable), but it is also not receiving any oxygen to its roots, which can damage the root system.

When a plant is allowed to go too dry (again, another risk inherent in long irrigation frequencies), roots can also be damaged: the obvious way is through desiccation, when root tissues dry out, collapse and die. But there is another danger: when a plant`s soil is dry, roots, in effect, suck harder at the soil to try and take up as much water as they are able (this isn’t technically exactly how it works, of course, but I’m not getting into capillary pressure, vapor pressure deficit, etc. here) to compensate for the water loss from the leaves through transpiration. If a plant is watered heavily at this point (and we`re all guilty of really soaking a plant that has gone too dry, mostly out of guilt), the plant takes up too much water too quickly, and the cells of the roots can rupture and, you guessed it, die. Proper restoration of a plant that has gone too dry involves gradually bringing soil moisture back up to a level where the plant can take it up without damage, which can take several hours’ worth of applying tiny increments of water to be successful. (Best, perhaps, to never let it get to that point, although as an aside I have heard that some plants can respond to drought stress by flowering, Spathiphyllum and Nematanthus among them.) It is perhaps a lot to ask someone to spend half their day watering one plant every half hour, and there are, to be fair, at least a few species which seem not to mind going from bone dry to wet, in my experience. Just be aware that this can be a concern.

The diagram to the right shows an example of a moisture release curve, which illustrates the availability (and unavailability) of soil moisture to plants. In this, case, anything above about 75% and under 20% is pretty much unavailable to plants, and furthermore those extremes can be dangerous to plant root health. So in order to optimize water uptake and keep our root zone healthy, we need to keep the water between (again, just in this hypothetical instance) 20-75%. How do we do this? Water more often!

This is where the weekly watering, as opposed to bi- or tri-weekly, can be a very useful tool. If we apply smaller amounts of water more frequently, we can maintain a more balanced soil moisture level, without the wild swings of ‘feast and famine’ watering. In this way we can keep the plant as close to its preferred level of moisture as possible for as often as possible, allowing the plant to grow its best without periods of inactivity or even stress.

Stay tuned for the next installment; How Much Water, wherein I don’t tell you how much water to give your plants.

The Carboniferous garden: Afrocarpus gracilior, Zamia furfuracea, Asplenium
nidus, Microsorum pustulatum and Psilotum nudum. Image © In Situ Plants. — The Carboniferous garden: Afrocarpus gracilior, Zamia furfuracea, Asplenium nidus, Microsorum pustulatum and Psilotum nudum. Image © In Situ Plants.

Cyclosephala colasi on a Philodendron inflorescence. Photo © Marc Gibernau/Denis Barabé; retrieved from the International Aroid Sciety website.

“Humanity is exalted not because we are so far above other living creatures, but because knowing them well elevates the very concept of life.”

-E.O. Wilson

One of In Situ’s primary goals as a company is to increase interest in plants in order to reconnect people to the natural world. We believe strongly in the hypothesis of biophilia, first conceived by the venerable E.O Wilson; the human need to commune with other living things. We feel as though this is why people have always kept plants indoors, and that now more than ever it is important to continue the relationship.

We use several strategies in order to further this goal of increasing interest in plants: making use of the wide variety of less-often used species is a good example, as the visual impact is immediate and apparent. Beyond plants’ appearances, however, lies the really fascinating stuff, and this is what we like to bring to light in our designs.

Even the most commonplace species can hold fascinating features when they are brought into context. For instance, the humble Philodendron, long a staple of interior landscapers, has a unique aspect to its physiology. The inflorescences (flowers) of many species are thermogenetic: they produce heat. And quite a lot of it, as well: some species’ inflorescences can rise 10°C above ambient temperature! This interesting adaptation serves to volatize aromatic compounds that attract pollinators, of which beetles are usually the primary ones. See here to read more about thermogenesis in plants.

The above is just one example of the countless facets through which one can look at plants. There are many themes which we have explored; below are but a few.

Biotopes

Plants’ natural habitats are, particularly in the case of the tropics, richly populated communities of species, with many growing closely around (or on, or in) each other. These ecological landscapes are referred to as biotopes, and these are interesting themes to explore, as they offer us a (somewhat stylized and selective) glimpse into where these species are from. To actually see these habitats in person is incredible, and we want to share this with our clients. Using solely plants from a particular region can highlight, for example, an area under grave threat of deforestation, highlighting the need for conservation.

Natural Variation within Species

The world of plants is one of incredible diversity, and even within species, an incredible amount of variation can be seen (see this post for more thoughts on this). Another perspective on this variation is convergent evolution, in which completely unrelated species evolve similar forms to solve the same problem. For example, many of the Euphorbia species from Africa and Madagascar often look for all the world like cacti (which are only present in the Americas), but are from a completely different family. These disparate species have come upon similar means of water storage (water-holding stems) and self defense (spines) that allow them to exist in some of the harshest habitats on earth.

Epiphytes

The epiphytes include many of our favourite plants, and many species which people are used to seeing in pots actually spend their entire lives without ever sinking their roots in soil. Orchids and Tillandsia bromeliads (the now very popular ‘air plants’) are some of the more commonly recognized ones, but the vast majority of tropical plant species are in fact epiphytic. Some of the more common epiphytes available are lipstick vines and goldfish plants (Aeschynanthus spp. and Columnea spp., respectively), begonias, many aroids such as Anthurium and Philodendron, and many ferns. Using exclusively epiphytes together allows us to see the richness of these plant communities living far from the forest floor.

The planting pictured here is a good example of how we are able to execute the types of themes we explore, and also of how we, too, learn something new about plants nearly every day. We really wanted to make use of a particular tree, Afrocarpus gracilior, (also known as the Weeping Podocarpus), as the texture of the foliage and its dense, shaggy habit makes a really dramatic statement. It is also unique in that it is a tropical conifer, distantly related to our familiar spruce and pine. This group of plants, the gymnosperms, does not produce flowers, though it does produce seed, and arose during the Carboniferous period of Earth`s history, some 300 million years ago. It is this latter fact that we decided to explore for this planting.

The Carboniferous is so named due to the fact that this is when the great forests that were destined to eventually be swallowed by the ocean and preserved in the familiar form of coal were at their peak. It would have been a different landscape than the one we are used to today, for flowering plants had not yet evolved, and more simple plants dominated the prehistoric flora. Among these were the simple vascular plants which reproduce via spore such as ferns, tree ferns, and allied families, and the first seed-producing plants, of which A. gracilior is one.

Another primitive plant which produces seed but no flowers is Zamia furfuracea, also known as the cardboard palm. This is a cycad, related to the more commonly seen Cycas revoluta or sago palm. This plant was definitely a candidate for this installation, and its coarse texture and olive colour contrasted perfectly with our Podocarpus.

We had to represent the family of ferns in this planting (being one of the dominant flora of the Carboniferous), and chose two that highlighted the extraordinary diversity of form seen in these plants. Asplenium nidus, the birdsnest fern, with its rosette form of bright green, undivided fronds, is an epiphytic fern that grows on trees in Australasia. Microsorum pustulatum, the kangaroo fern, takes another approach to its growth: it creeps along on a hairy rhizome, from which emerge deep green, incised fronds which are more classically ‘fern-like’ than A. nidus.

One final plant was used in this installation: Psilotum nudum, the whisk fern. This species was chosen more for its story than for its form, which is nevertheless an attractive bunch of semi-erect stems, from which are produced spherical synangia, which contain the spore the plant uses to reproduce. The species has no leaves, no roots, and only half a vascular system, and is very primitive indeed in its physiology, and was a must-have for this planting. What we discovered in our research, however, was that there is some evidence that suggests that P. nudum may actually be descended from more complex fern species, and that it may have reverted for some reason to this very simple form. Perhaps we will never know for sure, but P. nudum is definitely a great representative for other similar species which were prevalent during the Carboniferous.

These themes tend not to be immediately apparent to the casual observer, of course, unless the plants are unified by a physical characteristic, and so the obvious question is why bother? We are able (and would be more than happy) to produce educational signage for anyone who wishes to show off the subtleties of their interior landscape, but we feel that with this much intent in our work, there will be a mood created which is tangible, and which adds depth and value to our landscapes. We hope to draw the viewer into our world and experience plants on a new level, and to connect them with a world most urban residents would never encounter otherwise.

Tag: toronto

More Thoughts on Variety in the Interior Landscape

Why You Can’t Live Without Plants

On Biophilia and the Value of Interior Landscaping

Some Notes on the Natural Habitat of Tillandsia spp., and Inferences Therefrom on their Care in the Interior Environment

Ferns from Scratch, Part Two

Plants at Work- The Science Behind How Plants Improve Life Indoors

Watering 102: A Guide to Watering Interior Plants, Part Three

Watering 102: A Guide to Watering Interior Plants, Part Two

Watering 102: A Guide to Watering Interior Plants, Part One

Thematism in the Interior Landscape