Updated at: 23-04-2022 - By: Sienna Lewis

To keep a tiny greenhouse cool in the Spokane WA area, you can employ ventilation, shading, dampening, and soil moisture retention. When the weather is hot and humid, these are the stress-free techniques to maintain the right temperature for your crops.

Stable conditions are necessary for the growth and productivity of plants. Plants can thrive in a controlled environment in the greenhouse, unlike in the open field.

Let’s get a handle on the weather in Spokane, WA, so that you can better grasp how to keep a greenhouse cool.

Understanding Temperature Levels In Spokane

Temperature is the first thing to control in a greenhouse to ensure a healthy harvest. A temperature of 80 to 85 degrees Fahrenheit is ideal for the inside of a home.

In Spokane WA Area How To Keep A Small Greenhouse Cool - Krostrade

For greenhouse farmers, excessive heat might pose an issue. Tomatoes, peppers, and eggplants, for example, may withstand high temperatures without harm. If the temperature isn’t just right, some plants won’t grow.

Plants that are susceptible to heat such as carrots, lettuce, broccoli, and cauliflower need to be grown in cooler temperatures. Because of this, it is essential to learn how to maintain a consistent temperature throughout the year.

Most greenhouse crops are unable to thrive in Spokane, Washington, because the area experiences temperatures ranging from 26 to 88 degrees Fahrenheit throughout the year. In spite of the difficulties, there are ways to ensure that your greenhouse remains cool enough to protect your crops.

In this article, we’ll show you how to regulate the greenhouse’s temperature in the sweltering summer months.

How To Keep A Greenhouse Cool in Spokane, WA

These tips will help you cool down your greenhouse when it gets too hot, especially in Spokane WA. Read on for more information. It’s not difficult to maintain a cold environment in a small greenhouse.

Take a look and see for yourself by reading on!

#1 Ensure proper ventilation

Airflow is a great technique to keep your greenhouse from overheating. Ventilation can be achieved through the roof, side, and door vents. Vents like these are useful for removing heat from overheated plants.

The temperature in your greenhouse should always be monitored. When the temperature reaches 81 degrees Fahrenheit, plants can be harmed. As a result, a maximum-minimum thermometer is useful in this case.

Open all doors and vents as soon as possible on sunny days to begin ventilation. Installing automatic vent openers can make your life easier. It’s also a good idea to open the door to get the cooling process started in the event that automation is slow.

Also, keep them open on warm nights whenever possible. Keep cats and other rodents out of your garden by using pegging netting, but make sure the netting allows pollinators to get in.

#2 Create appropriate shading

In order to keep the greenhouse cold, the second way is to provide shade. However, this method must be employed because plants require enough light levels in order to grow to their maximum potential.

To reduce the intensity of the sun’s rays on the plants, simply painting the greenhouse is an effective and simple solution. You can layer up when the summer heats up. Use water-based and brush-washable paints.

External or internal blinds can also be used in place of paint. By blocking the sunlight from entering, the exterior blinds are by far the most efficient option. Installing an internal blind is an option if you have the funds to do so. The blinds should be installed distant from the vents to avoid obstructing airflow.

Mesh or shade netting can also be used to reduce the amount of light that enters the room. Because it’s cheaper than blinds and much easier to install, this is a great choice. When the vents are open, this can serve as wildlife protection.

#3 Damping down

Another option to employ when it’s too hot is dampening the greenhouse. The humidity is raised by sprinkling water on the hard surfaces, pathways, and staging. When water evaporates, the moisture level in the air rises, making it more difficult for pests to survive and allowing plants to better withstand the heat.

Do this as often as possible because it is crucial when it’s steaming hot. It’s best to water the greenhouse at least twice a day if it’s unlikely to stay damp all day. Once in the morning and once at night, mist the surfaces.

#4 Prevent water stress

Any plant will die if its soil is too dry. Crops that have enough moisture in their roots are more likely to grow well than those that lack it. Transpiration is a mechanism plants use to keep themselves from drying out. Overheating and wilting can occur as a result of a lack of this capacity. As a result, providing water to keep it going is critical.

Always keep an eye out for indicators of heat stress in your garden. It’s necessary to moisten the soil if it displays signs of wilting, burned leaves, or dry young foliage. These symptoms can be avoided by regularly watering your plants.

But you can’t be on the lookout all day for drying soil. You can use a variety of methods to maintain the soil’s moisture level stable. Hydroponics or a self-watering plant can be used, however hydroponics is a more environmentally friendly option.

Start-up costs for hydroponics are higher, but the benefits far outweigh them.

What temperature is too high for your greenhouse?

Any temperature above 90 degrees F (32 degrees C) is considered too hot for a greenhouse. The ideal temperature for a greenhouse is between 60 and 70 degrees Fahrenheit. If you live in a location where the temperature frequently reaches 100°F (38°C), this could be a serious challenge.

The optimum growing conditions for your plants will be compromised if the temperature in your greenhouse rises too quickly throughout the summer.

10 Ways to Keep Your Greenhouse Cool in Summer

What’s a good temperature inside a greenhouse?

Temperatures between 80°F and 85°F (26°C and 29°C) are generally considered best for houseplants. When all is said and done, though, it all comes down to the plants you’re growing.

Some people prefer it when it’s cooler outside, while others prefer it when it’s warmer. Keep this in mind while planning greenhouse gardening projects. Maybe you’ll save the hot-thumpers for the summer and the cold-thumpers for the winter.

10 ways to keep your greenhouse cool in summer

In spite of the summer’s high temperatures, you may still supply the ideal temperature for your plants. Plants you’re growing and your location will determine how much cooling is necessary.

1. Install a thermometer

If you don’t already have a thermometer, you should get one. This will let you keep track of the greenhouse’s temperature. In order to maintain proper growth, you can use a conventional thermometer to monitor your body’s temperature.

2. Ventilation for great air flow inside the greenhouse

A ventilation system must be installed in every greenhouse. As a result, before considering any other cooling method, be sure your greenhouse has adequate ventilation. For example, appropriately positioned roof windows and louver vents can do this.

During periods of extreme heat, you can expect the temperature inside your greenhouse to be 10-20 degrees Fahrenheit higher than the ambient temperature. Your plants will suffer as a result of this situation. To keep things cool, you have a choice between a natural and a mechanical ventilation system.

You may simply utilize side and base vents, in addition to roof vents, to quadruple the airflow when using natural ventilation in your home. It’s also a good idea to leave your doors open to bring in some fresh air. Using an automatic vent opener eliminates the need for you to be home in order to keep your greenhouse cool. Because of their temperature-controlled actuator mechanisms, they open and close automatically. It is possible to install them in order to improve airflow and preserve the growth of your plants.

For medium or large greenhouses, natural ventilation may not be sufficient if the temperature outside rises above a certain level.

Because of this, you’ll need to use mechanical ventilation, such as an exhaust fan. In order to keep your greenhouse cool, you’ll need a good ventilation system.

3. Using greenhouse fans

Slowly but surely, you’ll be lowering the temperature in your greenhouse. Keep in mind that even if you’re inside or outside, the air will still be used. If it’s 90°F outside, don’t expect your greenhouse to cool down much with an exhaust fan.

There are a variety of fan systems to choose from. However, before putting up a fan system, you need think about a few things.

Consider the size of the fan you need for your greenhouse first. You’ll need to figure out what your building’s ventilation rate should be. This is something that a professional can assist you with. Once you get above 8 feet, fans should be able to deliver one air exchange every minute at a minimum.

The location is also an important consideration. Because hot air rises (in the case of exhaust fans), it’s best to mount your fan at the very top of the structure to keep it clear of the plants. The hot air is expelled using exhaust fans. As a result, the greenhouse’s intake shutter (louvered vent) should be placed on a different side. Installing it near the bottom will help it draw in cooler air.

Additionally, the addition of louver vents to a standard greenhouse fan boosts airflow. Either place them behind the fan to allow the fan to draw in cooler outside air, or place them at the top of any wall to allow hot air to escape.

Maintaining your fan systems on a regular basis is also vital for their long-term performance. Cleaning fan blades, belts, and motors can help extend the life of your fans. If you live in a hot area, evaporative cooling may be your best option.

4. Cool your greenhouse with evaporative systems

Evaporative cooling systems are efficient and reasonably priced. They cool your greenhouse by 10 to 20 degrees by evaporating water with heat! When the humidity is low, they perform better. Fan-and-pad cooling systems are the most prevalent type of evaporative cooler. They chill the greenhouse by pulling in heated air through the pads.

In order to cool the air, a fan-and-pad system uses an above water supply and a gutter to collect water on an absorbent pad. Warm air is drawn into the pads by fans on either side. In this way, the pads are kept moist at all times, and as the water turns into gas, it absorbs the heat.

Your greenhouse’s evaporative cooler must be chosen carefully. To cool 20 square feet of floor, you’ll need about one square foot of pad. Your evaporative systems could be more efficient if they were cleaned on a regular basis.

5. Install a misting system or a fogger

Evaporative coolers are very similar to these cooling methods. They bring the fever down to a more manageable level. A mister/fogger is a modest choice that will work perfectly if you live in a cooler climate.

Water droplets are emitted through nozzles in misters and foggers to chill the air. The temperature drops when water evaporates. Foggers, on the other hand, produce smaller droplets and are more effective at cooling.

They also contribute to raising the relative humidity. Misting systems and foggers won’t be as effective in a region with high humidity because the air is already saturated.

6. Damping down

Another way to keep your greenhouse cool is to dampen it down. Misting is a lot like this. Even in extreme heat, it aids in plant cooling. Plants are able to withstand higher temperatures thanks to this approach, which raises humidity. You may easily accomplish this by drenching hard surfaces in greenhouses, such as walkways and staging.

Moisture levels rise with evaporation, which helps ward off pests. It’s fine to mist your greenhouse as much as you like, but don’t go overboard with the misting in the summer.

7. Water your plants adequately

In order to maintain your plants flourishing and healthy, you must provide them with the proper amount of water In order to maintain plants healthy and cool, they need to be watered properly. How? During transpiration, plants cool themselves by evaporating water from their leaves.

In particular, tropical flora like orchids are at risk. Your plant may be dehydrated if the edges of its leaves are browning or withering.

8. Install a portable air conditioner

Using a portable air conditioner to cool greenhouses is also an excellent alternative. They’re economical and save you money on your energy bill. The majority of them include a dehumidifier.

As a result, they’ll assist keep your greenhouse cool while also regulating humidity levels. Lean-to greenhouse owners can simply vent their air conditioners into the greenhouses, making it easier for them to grow. On the other hand, due to their high cost, air conditioners might not be an option for those with tight budgets.

9. Use plants strategically

Another way to keep your greenhouse cool in the summer is to use natural methods. When it comes to evaporative cooling, plants are the best. Large-leaved plants like grapevines and fig trees will help keep your greenhouse cool.

Having big leaves that allow water to be evaporated and shade the soil is beneficial. Just think about it: Now you’ll be able to keep the warmth down and protect your soil while reaping the benefits of delicious fruits.

What’s this? A greenhouse that is shaded by plants is another option. Simply building your greenhouse next to a deciduous tree can provide you with enough shade to keep your plants healthy.

How To Keep Your Greenhouse Cool in the Summer | Family Food Garden

Your greenhouse can benefit from year-round protection from deciduous plants. When its leaves fall in the winter, it serves as a source of light during the dark months. Its leaves, on the other hand, will regrow in the spring, providing you with the much-needed relief from the hot heat.

However, putting up a greenhouse too close to a tree is not a good idea. This could have negative consequences. Also, if you live in the extreme north, you should not do this. In the spring, fall, and winter, you’ll want as much sunlight as you can get. Shade cloth is a preferable option in this situation.

10. Creating shade for less sun exposure

In order to reduce the temperature of the greenhouse, you can use shade cloths and curtain systems. Because it’s not a solid roof, don’t expect a huge plunge.

These cloths might also come in handy if your plants get burned by the blazing sun. Internal curtains can be installed and closed as needed. It is possible to cover the entire greenhouse with external shade cloths, which tend to provide a somewhat better insulation from the sun’s heat.

There are a variety of shades and densities to choose from when it comes to greenhouse shade cloth (e.g. 30 and 90 percent shade). Using these percentages, you can see how much light is being blocked out of your greenhouse. How much of a density should you utilize, then?

Your greenhouse’s architecture and the light needs of your plants will all play a role in this. Vegetables, on the other hand, are best served by light shades of 30 to 50 percent. In the case of ferns or orchids, a 50% gradient can be used, while other plants can benefit from a higher shadow.

Curtain systems can have a significant impact on the environment in your greenhouse and reduce plant stress. Make an effort to use curtains made of long-lasting materials. Polypropylene, polyolefin, and aluminet are all good options. A small amount of heat is reflected by the latter two materials.

Why should you keep your greenhouse cool in summer?

If you’ve read thus far and are still unsure about whether or not it’s worth your time, effort, and money, then let me explain the dangers.

If you don’t maintain your greenhouse cooled, you’ll lose all of your hard work in the long run. How? Hot weather increases the risk of pests and illnesses in your plants. Temperatures above 90 degrees Fahrenheit can cause them to wilt, dry out, or get anxious.

It’s possible for them to completely stop creating new growth in extreme circumstances. As a result, little or no yields are to be expected. There are many plants, especially vegetables, that thrive in chilly circumstances, and going beyond this might have a negative impact on their health and growth.

In the summer, should you abandon greenhouse gardening? Maybe. For those who want to start their plants in a greenhouse and take them outside for the summer, do so! A properly cooled greenhouse will help keep bugs and other vermin at bay and keep your plants healthy.


Despite the sweltering conditions in your greenhouse, you can still be a successful grower. If you use the methods outlined in this article to their full potential, you can expect a plentiful crop year after year. A modest greenhouse isn’t that difficult to keep cool in the Spokane region of Washington.