At Greenhouse Emporium, we’ve nurtured our fair share of gardens and know a thing or two about the dance of sunlight and shade. Today, we’re diving into the nifty tricks of how to cool a greenhouse without electricity, ensuring your verdant sanctuary thrives even when the summer sun does its best to turn up the heat.
In this article, we’ll walk through a series of steps that have stood the test of time and our own rigorous trials. From the simple act of venting to the clever use of shade cloth, we’ll cover all the bases. We’ll also touch on the ideal temperature for your greenhouse and why keeping it cool is vital during those scorching summer months.
So, roll up your sleeves, because we’re about to get into the nitty-gritty of keeping your plants happy and your greenhouses cool, all without plugging into a single kilowatt of electricity.
How to Cool a Greenhouse Without Electricity
Venting the greenhouse
From our experience, the simplest solutions are often the best, and when it comes to cooling, venting is your greenhouse’s best friend. Hot air, being less dense, will naturally rise, seeking an escape through the highest point.
By aiming for vents that account for about 40% of your floor area, split between the roof and sides, you create an efficient escape route for this warm air. Imagine a chimney effect, but for your greenhouse.
Proper ventilation is also one of the key ways to heat a greenhouse without electricity.
Evaporative cooling
Evaporative cooling might sound high-tech, but it’s as old as nature itself. Here’s the gist: as water evaporates, it absorbs heat, reducing the temperature. By wetting the outside of your greenhouse or maintaining a humid interior, you can lower your unheated greenhouse temperature by cooling the air as it enters.
Our trials have shown that when you pair this with good venting, the results can be quite impressive. However, it’s a delicate balance — too much humidity can invite mold or harm certain plants. It’s about finding that sweet spot where the air is cool, and the plants are perky.
Misting systems
A misting system offers a refreshing mist that keeps the humidity levels optimal. Yes, it typically requires a pump, but don’t let that deter you.
A solar-charged battery system can power your misters, aligning with our electricity-free ethos. It’s a small investment for a significant drop in temperature, and your plants will thank you with vibrant growth.
Solar-powered cooling fans
Harnessing the power of the sun, solar-powered cooling fans can be a cornerstone of your greenhouse’s climate control. These fans circulate air, preventing the stifling stillness that can stress your plants on hot days.
They’re especially useful in larger greenhouses where air can become trapped and heat can accumulate. With solar panels, these fans transform sunlight into a cooling breeze, ensuring your plants enjoy a gentle, refreshing airflow.
If you’re thinking about using solar panels for your cooling system, you might also want to learn how to heat a greenhouse with solar panels.
Shade cloth and shading
Shade cloths serve as a gardener’s frontline defense against the intense sun, moderating greenhouse temperatures by casting a protective barrier that reduces light intensity and heat. The density of these cloths, indicated by percentage, directly correlates with their shading capacity—higher percentages yield more shade and cooler conditions.
For example, our UV-resistant knitted shade cloths demonstrate how a fabric can offer durability and light control, while our robust woven cloths provide a heavier, more sun-stable option.
Keep your insect screens clean
Insect screens are a double-edged sword; they keep pests out but can also trap dust and debris, which impedes airflow.
A regular cleaning schedule ensures that your screens are not counterintuitively contributing to a temperature rise. Plus, it’s just good hygiene practice for your plant’s health.
Use deciduous trees as cover
Deciduous trees are nature’s own shade cloth. But, can you put a greenhouse in the shade? As long as your plants are still getting at least 6 hours of sunlight a day, there’s no problem with taking advantage of tree cover.
By planting your greenhouse beneath these seasonal wonders, you’ll have lush, leafy coverage during the summer, which naturally dissipates as the trees shed their leaves in the fall, allowing more light in when it’s needed.
Use the prevailing winds
Lastly, don’t forget to consider the prevailing winds when you position your greenhouse. A well-placed structure can take full advantage of natural breezes, which can be as effective as any mechanical cooling system.
It’s about working with the environment, not against it, to create a sustainable and comfortable atmosphere for your plants.
What’s the Ideal Temperature for Your Greenhouse?
The general sweet spot for most plants hovers between 60-75°F during the day. This range is warm enough to promote active growth without causing heat stress. As the sun dips below the horizon, so will the minimum greenhouse temperature. A cooler ambiance at night encourages plants to respire and recover from the day’s heat.
Why is it important to keep your greenhouse cool during summer?
Summer’s scorching days can turn your greenhouse into an oven, and not the kind that’s helpful for baking pies. High temperatures can push plants beyond their comfort zones, leading to heat stress.
This can manifest as wilted leaves, sunburn, poor fruit set, or even plant death. It’s not just about survival; it’s about quality. Plants that are too hot can’t produce the lush foliage, vibrant flowers, or juicy fruits that we strive for.
