11 Ways to Cool a Greenhouse Without Electricity

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A greenhouse is a terrific way to garden all year long. These days, greenhouses come in all different shapes and sizes. It doesn’t matter if you’re on a farm or have a small backyard, you can find a greenhouse that works for you.

One of the best things about greenhouses is that they regulate temperature conditions to make it possible to plant flowers or vegetables that would otherwise struggle in the climate you’re in.

For example, if you live somewhere very dry, then you’re going to have a hard time raising crops that thrive in humidity. A greenhouse makes it much easier because you can mimic conditions of their native climate.

Most people with relatively little greenhouse experience assume they always have to be hot. That is usually the case during winter, but greenhouses also need to be cooled in summer.

If you’re growing fragile plants or planting new seeds, then you need to keep things relatively cool so they don’t overheat and die.

Some higher-end greenhouses have cooling systems installed, but that’s not for everyone. How do you cool a basic greenhouse without electricity to keep your plants alive and healthy?

We’ve put together this list of 11 things you can do to keep your greenhouse cool when things heat up outside.

Small greenhouse setup in the backyard

Make Sure There Is Good Ventilation

Air flow is perhaps the best thing you can do to cool your greenhouse without using electricity.

It’s easy for temperatures to spike when air is static. You’ll walk into your greenhouse and feel the difference in the air. Keeping good ventilation is like cooking with your oven door open.

It’s much harder to heat things up because the hot air is escaping. Hot air rises and cool air settles, so you’ll keep the cooler air in your greenhouse.

Knowing that hot air rises, though, you should install ventilation toward the top of your greenhouse for best effect.

Damping Down

Damping down refers to when you spray your greenhouse with water. Cool water lowers temperatures and makes it easier for plants to grow. The process is simple.

All you need is a hose. Turn it on and spray all of the hard surfaces on the outside and inside of the greenhouse. Be careful not to spray any small plants or seedlings directly with the hose because it could damage them.

When you damp down, you’re counting on the evaporation process to cool your greenhouse. As the water turns to gas, the energy in the process releases heat, leaving the cooler condensation inside to cool the greenhouse. It will be humid, but at least it won’t be as hot.

Glass greenhouse with open part of roof and door for proper ventilation

Strategically Position Your Greenhouse

Depending on the size of your greenhouse, you may be able to move it so it’s not in the direct path of the sun.

Track when temperatures are the highest during the day and where the sun is typically located at that time. Try to avoid the greenhouse being directly under the sun for hours when it’s the hottest outside. That will keep things cooler for your plants inside.

Use Shade Cover

If you live somewhere or your greenhouse is located somewhere with a lot of trees, then you can keep things cool without electricity by putting the greenhouse under shade.

You’ll sort of have to find the sweet spot to make sure your greenhouse doesn’t get too cool.

The sun also works to keep things warm enough inside for plants to grow, but shade will keep things from overheating.

Buy Some Shade Cloths

Shade cloths are another great option for cooling your greenhouse.

You can put shade cloths on and take them off depending on what temperature you’re going for inside. You can keep your greenhouse exposed to the sun and manage indirect sunlight at the same time.

Shade cloths are available online or at your local hardware store or gardening outlet. You can buy them in different sizes to fit your greenhouse. Just don’t block out all of the sunlight.

The goal here is to reduce heat by blocking some of the sun.

Use Mist Bottles

Misting is another way you can cool your greenhouse.

It’s similar to damping down in that you’re using water to reduce temperatures, but misting is a lot more direct. You’re counting more on the cooler temperature of the water rather than the evaporation process.

You can find an affordable misting bottle and, every so often, go into your greenhouse and mist hard surfaces as well as plants to make things cooler.

Automatic mist sprinkler in greenhouse

Paint the Outside of Your Greenhouse with Shade Paint

Shade paint is a bit more permanent of a solution than shade cloth, but it could work for you depending on what you’re growing and where you live.

One great thing about shade paint is that it’s affordable and easy to put on. All you do is paint the outside of your greenhouse like you would paint anything else.

Usually, one coat of shade paint will do the trick. Then, you can see how cool things are inside and decide if you want to put it on more thickly.

This is a bit of an older method because now shade cloths and installing vents typically work better.

Buy a Greenhouse with Roll Up Curtains

If you’ve already got a greenhouse, then this might not be worth it to you. Roll up curtains can be installed on existing greenhouses, but it’s usually a lot of work.

However, if you’re buying a new greenhouse and want to cool it without electricity, then curtains are a great option.

Curtains can be raised and lowered to release or trap as much hot air inside as you like. With curtains, you get better airflow, much like you would with vents, but the openings are larger to get air moving faster.

Consider Solar

We know that solar energy still technically counts as electricity, but with a solar panel you won’t be adding anything to your monthly utility bill. The cost of solar panels has gone down as they’ve become more common.

You can find a solar panel large enough to attach an exhaust fan that will push hot air in your greenhouse out efficiently. It will make having vents or curtains much more effective as well.

Solar panel on blue sky background

Install a Misting System

Some greenhouse suppliers will offer misting systems that will automatically mist the inside of your greenhouse to keep things as cool as you want it to be.

Much like a home sprinkler system, the misting system can work off of a timer, and you can decide how much water you want to use.

It saves you time from having to walk through with a misting bottle, and you’ll know that you’re getting good coverage with a misting system inside.

Greenhouse Shading Blinds

We’ve already touched on curtains and shading cloths, but you can buy a sort of combo of both with shading blinds.

Shading blinds are like a shading blind that you can extend or retract without having to take the entire thing off. It’s an easier way of controlling greenhouse temperatures with the tug of a string instead of hauling the shade cloth out of the shed each year.

If you have a larger greenhouse or one that’s tall and hard to reach, then this could be a great choice for you.


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