A greenhouse is meant to be hot. While simple window shades can turn down the heat, turning up the heat can be a lot more complicated. Design your greenhouse to be as hot as possible or make a few tweaks to make an existing one even hotter.
Glass greenhouses are dying out. Most greenhouses use polycarbonate sheets for their panels because of their ability to absorb and retain heat. Polycarbonate sheets provide more insulation (with more than 60 percent R-value compared to glass) while letting in as much sunlight as possible.
These sheets disperse sunlight as it passes, spreading the light more or less evenly around your greenhouse. Polycarbonate sheets also filter sunlight, preventing harmful ultraviolet radiation from damaging your plants. Switching panels shouldn’t be a problem as polycarbonate sheets are a lot easier to use than glass.
If you’re building a new greenhouse, building it partially underground can make it a lot warmer. Even a few feet of the earth around your greenhouse can provide extra insulation, especially during winter. Ground temperature usually stays at 32°F even if it’s freezing, keeping your plants safe even in the harshest of winters. The hot earth around your greenhouse during the summer will add a bit of warmth, which you can use to grow heat-loving crops like tomatoes and peppers.
Store Some Sun
If your greenhouse isn’t heating up as much as you’d like, you’ll need to use the sun to store extra heat in makeshift batteries. Black plastic barrels filled with water will absorb heat while the sun is up. The water inside will stay warm for quite some time, maintaining your greenhouse’s temperature through the night. Just make sure your barrels aren’t blocking essential sunlight from your plants. Take them out or cover them in white during summers to prevent excess heat.
Defend the North
The north side of your greenhouse probably won’t get enough sun (as long as you’re in the northern hemisphere). It will be better to opt for insulating panels instead of the usual glass or polycarbonates for the north side of your greenhouse. Use thermal insulation foils for added heat retention as it keeps the cold out while increasing the concentrations of sunlight within your greenhouse. You can also use bubble wrap for additional insulation. Just make sure to purchase horticulture and not packaging wraps.
The plants in your greenhouse are meant to be green and vibrant. However, everything else should be as dark as possible. Opt for black or dark-colored pots and containers for four plants. Add a layer of dark wood mulch over your planting beds, as well as the space in between them. Dark colors absorb and retain heat from the sun, and your greenhouse needs every bit of heat it can get.
A hotter greenhouse gives you more options. You can plant more crops and flowers or extend your growing season deep into winter. Take measures that will turn up the heat and make your greenhouse more efficient and versatile.