So your fall vegetable garden is going strong, but you hear freezing temperatures are in the forecast. How can you save and protect your plants from frost? A little frost and snow don’t have to stop you from having fresh veggies! One of the great things about living in zone 7 and zone 8 is how easy it is to extend the fall garden well into winter. No need for a fancy greenhouse. Protect your garden from frost and freezing with these four methods and a few inexpensive supplies to have delicious homegrown veggies year-round. Don’t let Jack Frost stop your garden this year!
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History of Frost Protections
While we often think of spring and summer as the only times to grow food, our ancestors have been perfecting year-round growing techniques for over 400 years! The Parisian market gardeners perfected seasonal extension in the 1800s using several of the methods we’ll be elaborating on below. For some modern day guides check out Eliot Coleman and Jean Martin Fortier on how to protect your garden from frost and freezing weather.
Cold-Hardy Crops
Different plants freeze and die at different temperatures. So you want to grow cold-hardy vegetables. You won’t be growing tomatoes in December, but there are plenty of vegetables that like the cold and can handle freezing weather. Some even taste sweeter when there is a little nip in the air. Consider some of these delicious fall and winter veggies:
For more cool weather crops, check out our top 10+ fall vegetables post.
Method 1 – Cloches
Cloches are easy and nearly free to make or you can invest in some specifically designed for the purpose–plastic or glass. These work great in tight places or even for container gardens. Repurpose your milk jugs or 2-liter bottles by cutting out the bottom and slipping them over your plants to protect your garden from frost.
Some things to keep in mind when using the cloche method:
1. Uncover when temperature rises. Don’t want to fry your greens before getting them to your kitchen!
2. Be mindful of windy days if using lightweight plastic. They might blow away if not weighed down with a rock or stake.
3. It does take time to cover and uncover individual plants. This method is probably better suited for smaller kitchen gardens.
Method 2 – Cold Frames
Not only are cold frames more aesthetically-pleasing than plastic milk jugs scattered across your yard, they also increase your growing zone by one number! There’s a big difference between plant survival between zone 6 and zone 7 temperatures. Cold frames are inexpensive to make from recycled wood and old windows. Plus, cold frames take less time to manage as you just have to pop the top when the days are warm or the sun is intense.
Things to keeping in mind when using the cold frame method:
1. Source your wood responsibly. Make sure it will not be leaching unwanted chemicals into the soil near your edible plants.
2. Uncover when temperature rises. Don’t want to fry your greens before getting them to your kitchen!
3. Pay attention to where the sun is in the winter sky. Build your cold-frames to angle toward the sun for maximum heat.
Method 3 – Low Tunnels
What if you’re growing more vegetables than can fit inside a cold frame or milk jug? Allow me to introduce the low tunnel. Low tunnels are like miniature greenhouse directly over your plants. They are easy to set up and an affordable option for larger fall and winter gardens. While you can use greenhouse plastic, we’d recommend (and personally use) Agribon. It’s like a cozy blanket for your veggies. Agrigon allows water and sunlight through, but prevents frost from forming on the tender leaves underneath. It takes less time to manage as you can leave the row cover on and just uncover when you need to harvest.
Things to keep in mind when using the low tunnel method:
1. Be mindful of wind. Weigh down your frost fabric or plastic with some bricks, rocks, or stones.
2. Snow is heavy. Consider using a stronger metal for the hoops if snow or ice is in the forecast.
3. Make sure fabric is not touching the plants. This will hold the moisture (i.e. future frost) on the plants instead of protecting against it!
Method 4 – High Tunnel or Greenhouse
Lastly, there is the larger and more permanent option of a high tunnel or greenhouse. They have better insulative properties. Meaning, they heat up more air over the day so the greenhouse stays warmer overnight. There are also options for adding heating to a greenhouse to allow for growing some non-cold hardy vegetables.
Things to keep in mind when using the high tunnel/greenhouse method:
1. Ventilation will be required on warmer days. Roll up the wall, install some vents, and swing open the doors. Greenhouses can get hot fast!
2. Watch out for pests, especially aphids & thrips. Pests can quickly take over in enclosed spaces!
3. Temperature will vary. The edge rows can be colder than the inside rows.
And now you have a variety of options to protect your garden from frost and freeze damage and keep those fresh veggies coming in all winter long. You can mix and match methods too. We have a cold frame for our herbs and use agribon low tunnels for our greens. We cover with milk jugs when we transplant our tomatoes a little too early in the spring. You can even put low tunnels inside a greenhouse to keep even the most tender of plants toasty on cold winter nights.