Keep Growing- The Science of DIY Greenhouses


The onset of cooler temperatures doesn’t have to mean the end of harvesting fresh vegetables from your backyard. DIY greenhouses can be built for less than $500 and will give you the space and means necessary to keep your garden going all year round.

 The Principles

Plants need five things to survive: light, warm temperatures, water, nutrients, and air. Greenhouses are designed to provide plants with light and warm temperatures – two things that we don’t get a lot of during the cooler months.

Light

Greenhouses are made of primarily translucent materials. The result is that plants are able to get plenty of light, unlike gardens or small plants that may have been brought inside to weather the winter months. More light means more opportunity for plants to perform photosynthesis.  On average, plants need six hours of sunlight per day to successfully photosynthesize. Placing your greenhouse in an area that gets full sunlight ensures that your plants will have as much time in the sun as possible.

Heat

Keeping your plants warm encourages photosynthesis and protects them from frost damage. Greenhouses are designed to help keep plants warm by capturing heat from the sun and converting it to infrared energy.

When light hits a solid object, the surface absorbs some of the energy and converts it to heat. Greenhouses allow light in because they’re made of translucent materials. Moreover, same materials make it difficult for heat to escape because it reflects into the greenhouse. The trapped energy converts to infrared energy and produces heat, keeping plants warm.

It’s possible for plants inside greenhouses to literally cook, so depending on how warm the day is, you may need to vent some of the heat. Also, greenhouses can’t produce heat without the sun: so, on gloomy days, you may need to find another way to heat the greenhouse, such as a space heater.

Thermal Mass

Another option to help your greenhouse retain heat is to use different materials. Materials with a high density take longer to raise in temperature and, consequently, longer to cool down. Materials such as brick, concrete pavers, and water can store a lot of heat energy. Adding these materials to your greenhouse can keep the greenhouse warm overnight, because the heat energy that they trap will be slowly released back into the air.

Build Your Own

Building a greenhouse in your backyard is simple. This video from Tree Hugger shows how to construct one for around only $300.

After you’ve got your greenhouse up and running, you can get to the fun part – choosing which plants to grow. Check out our helpful guide on plants with purpose and start prepping your outdoor living space for the spring.