3 Plants You Need in a Heatwave + More Reasons to Create Your Urban Jungle
Plants are having their moment in the sun (and shade). From Instagram-worthy “urban jungles” to fiddle leaf figs warming up the look of an all white, minimalist interior, it seems that plants are finally being paid the attention they so richly deserve. While we may be falling in love with greenery again for its ability to instantly make a home feel more, well, homey, plants have always worked to take care of us (food, shelter and herbal medicine, anyone?) and our planet. With excessive summer heat waves blanketing most of the country right now, we turned to Christopher Satch, M.S., Plant Scientist, The Sill, for a refresher course on plant biology—and to learn which plants we need in a heatwave to keep things cool.
Can you tell us how plants actually work to cool the air around them (and us)?
Heat is generated when light, or another form of energy strikes a surface, and it has nowhere to go. The energy is absorbed by the surface, and causes the particles to vibrate, which is what heat is—vibrating particles. Plants are master chemists, and use the power of chemistry to not only absorb that heat energy, but to transform it into useful energy, and redirect it. Through photosynthesis, light energy is captured and absorbed into biochemical reactions. I’ll spare you the details, but basically, the energy from light is absorbed and stored in the form of carbohydrates. Because it is captured and stored, not much heat is generated. Plants also absorb heat directly for use in other biochemical processes. They use the vibrational energy to catalyze other reactions within themselves. If only we humans could fund research to tap into that on a large-scale!
How much can plants help lower the temperature in an apartment/house? Is it five degrees? 10? Does it depend on the type of plant, and how many are in one space?
The quantity of heat removed by plants depends on how many plants are in the room, where they are located, and what type of plants they are. The plants need to be placed in the direct path of the sun. By being in the sunbeam’s path, the plant can maximize harvesting the light energy before it has a change to become heat. In the summertime, this is quite obvious outdoors if you stand under a tree that blocks the sun. However, standing under a tree that is shaded by a building doesn’t do much.
The size of the plant is another big factor. Simply put, the bigger and leafier a plant is, the more work it can do in reducing heat. Plants with large leaves tend to be great at that. Plants like succulents and cacti tend to not be that great at reducing heat for two reasons—the type of photosynthesis that they do (CAM) is different from regular (C3) photosynthesis AND they aren’t plants that cast shade. They survive the heat, and reduce it for themselves, but they don’t cool their environment. Otherwise, deserts would be fabulous places to be!
And of course, the more plants you have, the more heat-removal capacity you have as well. By loading up my windows in the summertime to the point of almost completely obscuring the window, my room is about 10 degrees cooler than it would have been if I let the sun bake my room to death with unobscured (south-facing) windows. The more of the window you block with plants, the more you’re going to reduce room temperatures.
What are your top three favorite indoor plants for helping to keep things cool during the summer months?
The Bird of Paradise plant (Strelitzia) is my top pick. Any other full-sun plant will be great at reducing heat. Large dracaenas, rubber trees and palms tend to be great as well (although palms are problematic with pests). Avoid cacti and succulents (and any dry, desert-type plant), as these do not reduce heat around them or shade anything.
Do we need a certain number of plants to make a difference? Will a few plants do, or should we aim to create an urban jungle?
Whatever number of plants that can block the most amount of sunlight that comes in will be most effective. The more you have, and the larger they are, the more effective they will be. “Urban Jungle Level” is what you need to aim for. Think about it: A field is cooler than pavement, and a forest is even cooler. Why? Because the sun is more effectively blocked in a forest setting, maximizing the absorption of light by the trees.
So, what’s your favorite thing about working with plants?
I love the diversity in the plant kingdom. People only get to see the same 10 houseplants over and over and think that that’s it, that there’s nothing more. In fact, that’s nothing—there are more than 391,000 different species of plants on earth. About 28,000 are orchids alone! I get to see the fun and wacky species and understand them. And if they pass our rigorous tests, I’d love to bring them in as new and interesting houseplants.
It’s also important to note that plants are often the forgotten underpinnings of society. Civilizations have risen and fallen based on plant harvests, but we so often take them for granted. We try to live our lives in such a synthetic way, caught up in our own human designs, that we often distance ourselves from nature. Like it or not we humans are a part of nature, and distancing ourselves from it only brings problems. Creating synthetic concrete cities without balancing them with plants has caused a heat problem in many metropolises. Often times the solutions are right in front of us, unnoticed, shading us with their leaves.
Searching for more ways to make your home even healthier? Discover the benefits of going clean with your laundry detergent.