GARDENING FACT SHEET:
Click to View Printable PDF file: “Protecting Plants from Frost and Extending your Season”
The Springtime gardening itch usually starts long before our last frost date has passed. And while we all try to keep the itch at bay until it’s deemed safe to plant, getting an early start is often too tempting to avoid considering our short growing season. Using season extenders is a great way to safely get that early start.
If you’ve found yourself elbows deep in soil while listening to the latest weather report warning of an upcoming freeze then don’t panic! We’ve all been there and there are things you can do to protect your plants AND extend your season.
Always water plants before a freeze.
Always water your plants before a freeze. Moist (not sopping) soil absorbs more heat.
Cover new, tender or budding plants with a frost cloth.
A frost cloth is a lightweight fabric that can be draped directly over plants. A frost cloth can provide up to 8°F of frost protection, depending on the weight of thecloth, and provides protection from the wind as well.
When covering your plants, it’s important to keep these things in mind:
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- To trap heat from the soil around plants at night, place the covering all the way to the ground. Covering plants like a “Lolli Pop” will offer little if any frost protection.
- Using blankets and sheets works well as long as the fabric remains dry. Uncover during the day so that the soil can heat your sheets or covers can dry.
- It is important to note that when using plastic as a covering, you must make sure the plastic is supported so it does not touch the plants, otherwise this can cause the plants to freeze.
- Black plastic nursery pots or 5-gallon buckets can be used on smaller plants as protection. This can give protection from frost, wind, and heavy snow. Top the flipped over bucket with a brick or heavy rock so it won’t blow away.
Reusable water-filled teepees provide significant protection when used.
The teepees work by releasing stored heat from the water to the plant. These have been shown to protect plants even when outside temperatures get as low as 16°F. These work great at protecting tomatoes or peppers in the spring.
Use cold frames.
Using cold frames is a great way to protect from frosts and heavy snow. Not only will it provide frost protection, but it will also increase growing temperatures for earlier crop growth and harvest.
A plastic covered cold frame typically provides 3°F to 6°F of frost protection. For cool season crops this can add 2 to 6 weeks to the beginning of your growing season and can be used in the fall too to extend the end of the season. Several trials done in Fort Collins, Colorado, have found that using cold frames greatly increases the length of our growing season.
In addition, these trials have found that using these additional measures can increase your protection even further:
Aluminum Space Blankets
Aluminum space blankets used to cover cold frames were shown to significantly add to the amount of frost protection. In Fort Collins trials, using a cold frame with a space blanket kept temperatures from dropping below freezing even when outside temperatures reached below 0°F.
Christmas Lights
Christmas lights were successful at adding frost protection. Using Christmas lights inside of a cold frame were shown to provide anywhere from 6°F to 18°F of frost protection.
Visit: https://cmg.extension.colostate.edu/Gardennotes/722.pdf for more information.
Click to View Printable PDF file: “Protecting Plants from Frost and Extending your Season”
