This is Part Two of a three-part series on ways to protect your plants from frost. Protecting your crops allows you to get an earlier start to your garden and harvest tasty crops long after the rest of your neighbors have put their gardens to bed for the winter.
Part One covers cloches and row covers. Today, we’ll cover hoop houses.
Introducing hoop houses
If you do an internet search for “hoop houses” you’ll find all sorts of green houses and structures of all sizes that food producers use to protect plants from cold temperatures. Most of them are designed for commercial producers who grow food year round inside these buildings.
The hoop house I’m talking about is much smaller. It’s a temporary tent-kind-of thing that covers a portion of your garden bed. It’s absolutely perfect for raised beds. You can use the frame of the raised beds or screw on braces to the sides of the bed to secure the PVC pipe (see illustration.)
Put a hoop house over your beds first thing in the spring and it will warm the soil so that you can plant crops four to six weeks earlier. The ambient temperature inside a hoop house will be 8°-12° warmer than the air outside.
That means you can plant cold hardy crops two months or more before your last frost date and you’ll be putting fresh vegetables on your table when most people are just starting their gardens.
How to make a hoop house
To make a hoop house you will need:
- 10′ long PVC pipes that are 3/4″ diameter (1/2″ inner diameter)
- a roll of heavy-duty clear plastic (get it in the paint section of the hardware store)
- something to secure the PVC pipe, (clamps or 1/2″ rebar cut into 12″-15″ lengths)
- bricks or stones to secure the bottom edge
- clothes pins or clamps to keep the plastic closed at the ends
In the illustration above, the PVC pipe is secured to the sides of the raised bed with a tube clamp. You can easily screw these into the frame of your raised bed. When I made mine, I pounded an 12″ – 15″ length of rebar into the ground at the edge of the bed, leaving about 4″-6″ of the rebar above the ground. Using rebar is also the easiest way to have a hoop house if you do not have raised beds.
(Watch the video)
Start watching the video at 6:11 to see how I made my hoop house.
Slip one end of the PVC pipe through the clamp or over the rebar. Then bend it over the bed and secure it on the other side with the clamp or rebar. You’ll want to space the PVC hoops about 4′-5′ apart.
Once you have all your hoops in place, cover it all with plastic sheeting. Here’s where these PVC clips (that I show in the video) come in really handy. Just clamp them on to the PVC pipe to secure the plastic and keep it in place.
Then you’ll want to secure the bottom edge so that the plastic doesn’t blow away on a windy day. You can use bricks or stones. Finally, close up the plastic at each end of the tunnel and secure the plastic with clothes pins to create a nice, snug green house.
Fill it with plants
Once you have your hoop house in place and it has had a chance to warm the soil, it’s time to fill it with plants. You can check the soil temperature with a kitchen meat thermometer. Just stick it into the ground to see how warm the soil is.
The soil needs to be 60° for cold-hardy plants and 70° for cold sensitive plant seeds to germinate. If you are transplanting cold-hardy plants that you started indoors from seed, the soil can be a little cooler, 55° – 60°.
As the plants grow, pay attention to the weather
conditions. Even if outside temps are close to freezing, if it’s a sunny day, the temperature inside the hoop house can get as high as 90°. Temps above 85° can harm new plants and cold-hardy plants simply won’t do well in high temperature. So if you’re having a sunny streak of weather, open up the north end of the tunnel for a few hours during the day. But be sure to close it up at least an hour or two before sunset.
Extending your gardening season
Once you’re sure that cold weather will not kill your crops, it’s time to take the plastic off for a season. Fold it and store it until the fall. Then in the fall, put the plastic back up so that you can extend your gardening season, harvesting fresh vegetables well into late fall.
Coming up:
In the third and final part of this series, we’ll talk about cold frames and how you might be able to have fresh vegetables all year long.
Pros and Cons
While hoop houses are a great way to protect your plants, they aren’t perfect. Here are some of the pros and cons to consider:
Pros:
Can cover a large area of the garden
Works well for both early spring planting as well late fall
Materials to make it are easy to find
Cons:
Will cost about $25-40 each
You’ll need to replace the plastic every few years
May need two people to set it up
May get damaged in high winds
Need to constantly monitor temperatures inside. You will need to adjust the covering to keep the temps moderate
