How To Winterize A Greenhouse

Horizon is proudly owned and operated in Manitoba—all of our sheds are built right here, in the heart of the Prairies.

For those of you who aren’t from around here, that means it gets cold in the winter. Very cold. 

We build greenhouses that will last a generation—if not longer. To withstand the test of time, though, you should take the time to winterize your greenhouse every winter. Our greenhouses don’t come insulated—but you can insulate them yourself and add heating sources if you’re planning on growing year-round.

This guide will teach you everything you need to know about winterizing your greenhouse. We can’t teach you how to winterize a greenhouse without teaching you what winterization is, though, so let’s get back to basics!

What Is Winterizing a Greenhouse?

Winterizing your greenhouse is simply the process of preparing your greenhouse for the winter months and preventing heat loss. Even if you don’t plan on growing anything in your greenhouse during the winter, you’ll still need to winterize it—the process will help to ensure the greenhouse structure retains its integrity through the winter.

We’ll also give you a few tips on winterizing in order to continue growing plants year-round, but that’s not the focus of this article—our goal here is to help you protect your investment. 

1. Deep Clean Your Greenhouse

Fall cleaning is as important as spring cleaning—if not more so. By decluttering and deep cleaning your greenhouse in the fall, you’ll be ready to go when the growing season starts again in spring.

When you start winterizing, you’ll start by deep cleaning the exterior of your greenhouse. You should clean the exterior glass and polycarbonate roof—the extra solar heat gain can help perennials survive through the winter, even if you’re not actively growing during the winter.

Once the exterior is cleaned, you’ll tackle the interior. This should include:

  • Washing pots to get rid of unwanted pests
  • Removing dead or unwanted plants from beds or pots
  • Treating beds and pots with fertilizer and water
  • Cleaning the inside of the walls
  • Sweeping and mopping the floors
  • Cleaning and disinfecting all surfaces
  • Cleaning and disinfecting tools
  • Decluttering by sorting and stacking tools, pots, and other items, then organizing them into different spaces

With everything cleaned and decluttered before winter, you’ll be able to pick up gardening in your greenhouse again in the spring with very little work.

2. Move Sensitive and Expensive Equipment to Storage

Ideally, you’ll have fans to circulate the air in your greenhouse. You may also have thermometers, soil testers, and more. 

Electronics can suffer significant damage if they’re left out in the cold, especially if they’re sensitive. Additionally, while greenhouses are rarely the targets of thieves and vandals, you can protect your property by removing any valuables from your greenhouse while it’s not in use during the winter.

Move any high-cost or sensitive equipment to your basement, to a locked (and preferably insulated) shed, or to your garage. 

You might keep some of your heavier equipment in your greenhouse over the winter – if it’s electronic equipment, ensure that it’s powered off to prevent wear and tear (and to avoid getting a pricey power bill!). 

3. Remove any Plants That Require Protection

This is the simplest step of them all—move any plants that require protection from cold weather out of your greenhouse, and into an insulated space. This is a great way to protect perennials that aren’t quite cold-hardy enough for our climate. You can move these plants into your basement, garage, or another insulated space. 

4. Close Your Greenhouse

Once you’ve cleaned out your greenhouse and emptied it of plants, electronics, and other equipment that you want to keep safe, it’s time to close up shop for the season. Ensure that all of your doors and windows are closed tightly, then lock your door. 

Ordering Your Next Greenhouse With Horizon Storage Sheds

Now that you know how to winterize a greenhouse, you’ll be ready to start your gardening season as soon as the temperatures begin to rise and as soon as you get that first whiff of fresh air in the spring. 

Need a greenhouse? You can order one with Horizon—our greenhouses are built to last a generation (or longer) with proper care. You’ll be able to garden more often every year—who could say no to that?