It’s easy to imagine how icy climates can leverage their natural resources to maintain a greenhouse. The glass of the greenhouse collects the sun’s warmth and the greenhouse gets warm, the same way your car gets hot inside even on a cool day. In cold climates such as Iceland, the greenhouse culture has transformed the country from one that had to import all of its produce to a country that grows much of its produce indoors. (Here are 5 surprising things gardeners can learn from Iceland's greenhouses.)
Hotter, desert climates present a different challenge. Deserts are often literal food deserts, with blistering temperatures that kill most plants. High winds can blow around sand that will also damage seedlings and structures. A traditional greenhouse that keeps heat in would be impossible in a climate that’s already too hot to support plant life.
A Way To Keep In Cool
So how can a greenhouse work in a region that’s already hot? It is possible to build a house in the desert—and keep it cool. It’s also a necessity. Hotter climates are those most affected as the climate changes, and it is essential that farmers in these regions find a way to produce food under increasingly harsh circumstances. Water scarcity will increase as world population grows, and food demand will also rise. Arid regions have developed new ways of growing that use little to no soil, clean solar energy, and have created astonishing methods for low water consumption.
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The elements of a desert greenhouse are quite basic, as uncomplicated as poles, insect netting, and possibly polyethylene, the thin plastic used in bags. In other words, the desert greenhouse can be as simple as a tent with poles firmly planted in the ground. The main goal is to create shade and create some sort of drip irrigation system that keeps the plants watered regularly.
Growing Tomatoes In Greenhouses Around The World
Across the arid (and icy) regions of the world, farmers have innovated ways to grow a tomato, possibly the world’s common food denominator.
In Nigeria, for example, desert greenhouses are proving quite popular for individuals and larger operations. A typical Nigerian desert greenhouse produces an abundance of vegetables and fruits, all inside a basic frame of poles covered with plastic sheets. The plastic netting keeps insects out, and provides a measure of shade and protection during the hot and rainy seasons. Enough air circulates inside the plastic tent to keep plants cool.
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Terjimin Farms in Nigeria makes simple framed greenhouses covered in thin polyethylene. The director of the farm, Samuel Aende, uses drip irrigation and soluble nutrients to grow tomato crops. His plants grow between 6 and 12 feet tall, and the greenhouses produces about 300 kg (roughly 660 pounds) of tomatoes every week. The farm had 15 greenhouses last year, after just four years in business. The frames last up to 15 years, even under punishing conditions from wind and rain.
Sundrop Farms in Australia is perhaps the world’s leader in hot climate greenhouse technology. Sundrop is headquartered in Port Augusta, South Australia, which is an unforgiving and harsh landscape. There is no fresh water in the area, the soil quality is exceptionally poor, and the heat is exceptionally hot; even the tourism bureau recommends you “seek shade whenever possible” and wear sunscreen above 30 SPF. It’s outback hot all the time. And yet…a tomato Eden has bloomed here.
Follow these simple instructions to save your favorite tomato seeds:
Sundrop Farms has few natural resources: plenty of sun, and plenty of seawater. They adapted their greenhouses to their environment. Their greenhouses use solar power as a source of free energy, much like the greenhouses in Iceland can use their naturally occurring hot springs as an energy source.
An even more exciting innovation: Sundrop desalinates their seawater from Spencer Gulf and converts it into fresh water. It’s an elegant solution to the fresh water conundrum. The seawater is piped to the farm, desalinated, and the water is used to irrigate crops, while seawater is used to keep the facilities cool. This astonishing system is powered by thousands of mirrors, which reflect the sun’s intense rays and turn the heat into a sustainable energy source. Sundrop Farms currently produces a staggering 15% of Australia’s tomatoes. For a fascinating overview of their system, watch this charming video.
Controlling The Water Supply
The desert greenhouse maybe simple to build, but the irrigation system is mission critical. When outside temperatures fluctuate, the water supply must remain constant. Greenhouses in a Mediterranean climate often contend with heat waves that can interfere with plant growth and production. The hot summer air is devastating to sensitive plants.
Related: This Native American Tribe Turned To Ancestral Farming Practices To Combat A Health Crisis
Israeli greenhouses also use desalinated water, like Sundrop Farms, and have been experimenting with a sprinkler system designed specifically for desert greenhouses called a “super fogger.” Rather than dripping water onto plants, this system creates a mist inside the greenhouse that protects plants from heat fluctuations. The super fogger was invented by NaanDan Jain Irrigation, a joint venture between India and Israel, and after several years of testing, it seems that the mist provides not only the right amount of humidity, but also keeps the greenhouse cooler. The super fogger lowered temperatures from 8 to 15 degrees, and the plants produced more fruit, even during the hottest parts of the summer. Yield increased by up to 30% when the plants were kept cooler and the greenhouse itself was misted, not just the plants.
A Soil-Free Greenhouse In America's Desert Region
America has its own desert region, and a vertical, aeroponic greenhouse blooms in Arizona. True Garden, in Mesa, uses no soil at all. Their greenhouse flourishes in a region that can easily reach 120 degrees during the day and cools off to the scorching 90° at night. Their greenhouses use large “tower farms” where seedlings grow in pockets in the tower. (See a rather mesmerizing time lapse of basil growing.) The metal-framed greenhouses create an indoor water cycle where the water re-circulates, and they use solar energy. The greenhouses depend on a venting system that keeps air circulating and energy usage low.
Related: 6 Best Hoop Houses And Greenhouses For Growing Your Own Food Year Round
True Garden is part of a system built by Future Growing, a company dedicated to creating urban vertical farms that use no chemicals, little water, and no soil. They also emphasize the importance of local farms, which reduces the need to truck supplies and food. Their produce is organic and the owners, Lisa and Troy Albright, provide food to their local CSA and to local restaurants. Troy Albright points out that “33% of Earth’s total landmass is desert,” so it’s essential that farmers learn to use their desert sun to their advantage. He emphasizes the importance for desert greenhouse growers to note the fluctuations between hot daytime temperatures and cooler evening temperatures.
For home gardeners in hot regions, a greenhouse is absolutely possible. Many kits are available, from the aeroponic tower to an entire greenhouse kit. You can even construct a basic greenhouse using a frame and UV stabilized plastic sheeting, so long as the greenhouse is properly vented to keep the air flowing.