Overwintering Plants In Hoop Houses

Snow, wind, rain, and cold temperatures can leave you with a lot of dead plants in early spring. Luckily, hoop houses can protect your plant inventory.

You worked hard all season in your backyard nursery caring for your plants so they can thrive. But now it’s almost winter and your plants are showing signs of dormancy.

First off… this is a normal and good thing. Dormancy is an important part of growing plants. Plants need to go dormant so they can have a period of rest.

When the weather breaks in the spring they will respond to the sunlight, warm temps, and rain, with an abundance of new growth and foliage.

For me, this is my favorite part of being a plant grower. Watching as my plants put on new growth during that spring growing spree.

But before enjoying the spring growing season there is one obstacle in the way. Surviving the winter!

Normally, for plants that are in the ground and in your landscape, you wouldn’t give two thoughts about the onset of winter. But for plants that are above ground, in pots, things are completely different.

The roots don’t have the natural insulation and protection that the ground has to offer. Instead, plants in pots are subject to temperatures that are pretty much as cold as the outside air temps.

They are also more vulnerable to wind damage, drying out, and drowning due to decreased drainage from being in a pot. These are all ways to lose a lot of plants, but fortunately there are ways to protect your plants over the winter so they can thrive in the spring.

Hoop houses have become one my ways to overwinter plants.

What Are Hoop Houses?

Hoop houses come in many different shapes, sizes, and materials. But when used for the purpose of overwintering plants they all have the same goal; providing a warmer climate for your plants, as well as keeping them protected from damaging winds, drowning rains, and heavy snow loads.

It is important to point out that even though you are putting your plants in a hoop house for the winter, you are still wanting them to be exposed to low temperatures so the plants remain dormant.

Think of a hoop house as providing you with a climate that is 500 miles south of your location.

Metal or Plastic Frame?

In my opinion, metal is really the only way to go. If you are in a climate that doesn’t get a lot of snow then you might get by with a more inexpensive plastic frame.

But here in Zone 5 New Hampshire we get some seriously cold and snowy winters. I like to make sure I have strong metal hoop houses. There’s nothing worse then a big snowstorm collapsing your structures.

Take a look at the pic below. These are 3 metal hoop houses that are being setup. They are about 12’ wide, 30’ long, and 7’ high.

In my opinion this is the perfect size. Plenty wide, long, and just high enough where I can walk through it but at the same time it’s not so tall that all the heat escapes to the top.

Three metal frame tunnels used for overwintering plants with plants underneath them — Building 3 metal frame hoop houses to overwinter hundreds of 3 gallon shrubs.

I bought the hoop houses above from Growers Supply and have yet to find a better value.

What Kind of Plastic Should You Use to Cover the Frame?

Once you get your metal frame installed it is important to make sure you wrap the frame in white plastic. White plastic will let some sunlight in, but not too much.

If you use clear plastic then during the day when the sun hits it might get too warm and your plants might start to break dormancy. This is the last thing you want!

Remember, you want your plants to remain dormant all winter until it is time for them to wake back up in spring.

How Thick Should Hoop House Plastic Be?

I would recommend at least 4 mil. 4 mil will last you at least one season but if you are careful it is likely to last longer. 6 mil is usually a safer bet for multi season use.

Do You Have to Water Plants During Winter?

Since hoop houses are covered, plants will not be receiving any rainwater. It is important to water plants as needed to keep them from drying out when in hoop houses. This requires regularly monitoring your plants.

Since watering can be tough during the winter I usually wait for a relatively warm day where I can fire up the garden hose and spend some time hand watering my plants.

In general I rarely have to water during the winter months. I think the most I’ve ever watered during the winter was twice.

Some winters I don’t have to water at all. Just make sure you are checking your plants regularly.

Hoop House Pros and Cons

Pros

Overwintering potted plants in hoop houses is probably the best above ground option in terms of plant survival. This is especially true for perennials. Perennials really don’t do good in pots over the winter.

Unlike shrubs their roots are much more delicate and will likely freeze if left in pots outside.

I make sure to put my most delicate and valuable shrubs and perennials in the hoop houses for the winter since this provides them with the best odds for above ground overwintering success.

Cons

The negative part about hoop houses is probably pretty obvious. For one, they are expensive. The ones that I have pictured above are about $850 each, with plastic and hardware. That is actually a really good price. It can go way up from there.

The other draw back is time required to put together these structures. Even though it is relatively easy, it does take time. You also need to make sure you have a large and flat space to build on.

If you are looking for an easier, and more affordable way to overwinter plants then consider using frost blankets.

You simply tip your plants over so they are laying down, and lay the blanket over your plants. All you have to do next is pin down the edges of the blanket so they don’t blow away. For added protection you can lay down multiple layers.