When you’re preparing your greenhouse for winter, the most important factor is whether or not you will heat your greenhouse. If you heat your greenhouse, you can use it to move some of your outside summer plants too, so they can survive the cold winters. If you don’t heat your greenhouse, check which plants can grow in colder climates. Protect your plants with our tips!
Most of these tips are focused on an unheated greenhouse, although many of them can also be used with a heated greenhouse. We have foreseen some extra info on heated greenhouses below!
Winterizing your greenhouse
Although I’m not particularly a fan of cleaning, this is one of those jobs that just needs to be done. Especially when the outside of your greenhouse is getting a little green, it’s important to get the windows clean. During winter, the light needs to be able to reach your plants and the sun needs to heat up your veggies whenever it gets a chance.
For the outside, it’s best to use a product that will also clean off the moss and fungi on your glass or polycarbonate panels. Make sure you get a different product for the inside, as this will be too aggressive to clean with so close to your plants. Try to find a biologically degradable product with no chemicals in it, so it doesn’t harm your veggies and plants.
2. Prepare the soil
Start by removing all dead plants and plants that might have picked up a disease during spring or summer. Placing some worms in the soil of the greenhouse will help you to make the ground airier and healthier to start planting again in spring.
3. Plant your winter greens
Does your climate allow winter growing? Not only Californa greenhouses can still produce vegetables during winter! Some veggies are well equipped to survive winters in a greenhouse. By the end of autumn, you need to start planting your winter greens, such as spinach, leek and carrots. Make sure you plant before frost hits because you won’t be able to dig into the ground when the soil is frozen.
To protect your greenhouse from frost, it’s advised to insulate your greenhouse. We have a whole article on insulating your greenhouse during winter (and summer for that matter). Take a look and increase your chances on healthy vegetables during winter.
5. Plant covers
When you are winterizing your greenhouse, you can also get extra plant covers. Each layer will make them better protected against frost and increase their chances of surviving winter.
While it may seem a little weird, even during winter you need to open windows and doors every once in a while. You don’t want the air inside your greenhouse to become too humid, this will have a negative effect on your plants. Open your windows during sunny periods and when temperature is below freezing to literally clear the air.
When you’re harvesting your winter plants, do it on the warmest time of the day. When you harvest frozen plants, they will break and you won’t be able to eat them. Wait until the sun is at its highest and harvest your crops.
8. Don’t water your plants (too often)
Sounds weird right? Trying to help your plants survive by not watering them? During winter, most plants are in ‘sleep mode’. Sleeping plants don’t need much water, especially not when it’s very cold. In winter you don’t need to water your plants more often than every 2 or 3 weeks, and it’s best to do so on a warmer day.
9. Location, location, location!
Are you setting up your first greenhouse? Figure out the best spot in your backyard to catch as much sun as possible during winter, but allow your greenhouse to benefit from some shade in summer. Especially when you want to grow in winter, you need every ray of sun you can get!
Heated greenhouse during winter
A heated greenhouse during winter will give you the opportunity to grow a wider range of vegetables and plants and to start growing spring vegetables earlier than in an unheated greenhouse.
When you have a heated greenhouse, you can use it to have your plants survive winter, so you don’t have to start from scratch during spring. You won’t make it as warm as a greenhouse would be in summer, the focus is on keeping frost out, so your veggies and plants don’t freeze and you can enjoy fresh homegrown vegetables all winter long. In our article on greenhouse heating you find all info about how to heat your greenhouse.
Are you ready to winterize your greenhouse? Do you have an ultimate winter greenhouse tip? Let us know!