Preparing the greenhouse for winter is as important as preparing the garden. However, it still is different. If you have been following our blog, you know we built a Geodesic Dome greenhouse ourselves. There are multiple ways to prepare a greenhouse, regardless of its size or shape; here are some suggestions.
Harvest the greenhouse
We harvest the greenhouse throughout the whole growing season, often starting with early peas and finishing up with figs and strawberries. But before the season is over, and the greenhouse freezes, you want to harvest all the tomatoes, peppers, and what else is ripe and ready.
The timing depends on whether the greenhouse is heated and its cover. If at this point there are still quite a few green tomatoes, harvest them all; green tomatoes ripen nicely indoors..
Empty the greenhouse
Remove all annual plants from the greenhouse, and also any pots or heaters that may have accumulated inside.
Please note that we do not recommend cleaning out the entire garden before winter. In the garden, we typically only remove plants like cabbage, which can create a significant mess, and any plants that have had diseases, such as powdery mildew. We leave perennials, sunflowers, and similar plants in place for insects to use as shelter.
In contrast, the greenhouse environment lacks a healthy balance of insects. Therefore, it is better to thoroughly clean the greenhouse and start fresh each spring.
If you have chickens, let them scratch in the greenhouse at the end of the season. Before letting them in to search for insects, remove all the pathway stones if possible, to ensure there aren’t any nesting insects.
Clean the greenhouse
Once the greenhouse is empty, use a garden hose to thoroughly wash it from top to bottom.
The car radiator and fan, which are part of our greenhouse heating and cooling system, as well as any vents or screens, also need a good clean. It is amazing how many things can build up there.
In addition to washing the cover and structure, also thoroughly water the soil to remove excess minerals that have built up, mimicking a good soaking fall rain in the greenhouse.
All of this cleaning and washing uses a lot of water, so take care to empty the water storage before winter. Last, clean the water tank itself if your greenhouse has one.
Cover the soil
Now that the greenhouse is clean, cover the soil with fresh mulch. You can use compost, well-rotted manure, or wood chips for this purpose. The mulch protects the soil and helps improve its quality. By spring, the soil in the greenhouse will be nice and soft, making it ready for planting.
Using the greenhouse in the winter
We have been asked whether we can grow anything in our geodesic dome greenhouse during the winter months. Since we are located in Zone 3, where temperatures can drop to -40 degrees, this is too cold for a simple greenhouse structure. Instead, we use an indoor growing room for our winter garden.
We generally like to start growing in the greenhouse as early as March, depending on the weather, of course.
Could we remove the cover since we are not growing anything in there? Yes, we could, but it would involve quite a bit of extra work. Additionally, we appreciate having the empty greenhouse available for storing garden furniture during the winter.
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Hi. First I love your blog and ive followed for awhile here and on FB. I just have a question of sorts. I Live in I believe zone 4a(Limestone ME)sort of NW of Caribou if you know anything about the area for reference. We love the idea of the geodome and have enough space that I think we’re going to go for the 4V(?) The coldest its been here in the last couple of years is about -12f not accounting for any wind. We’re bordered on the south side by open fields and there are more fields to the east. There is open land and then woods to the west(behind the house). The area gets a lot of drift in the winter. Does the geodome hold up pretty well to drifting snow? I know thats a lot of info for one little question, but i was curious.
In our blog post https://northernhomestead.com/geodome-greenhouse-winter/ we share a picture with the dome under a snowdrift. That’s about the most we have had. It might give you an idea.