By Barbara Pleasant, March 9, 2023
As gardeners, we face challenges that go beyond the daily weather forecast. While we might check if it’s going to rain or snow, we also need to monitor temperatures carefully, especially during the unpredictable spring months. Spring frosts can cause significant damage to tender plants, particularly if the temperature dips unexpectedly. Fortunately, there are simple ways to protect your crops, extending your growing season by a month or more. Below are three effective methods to safeguard your plants from frost damage.
Understanding Frost and Its Impact
Frost can be classified into four main types based on temperature, each with varying levels of risk to your plants. Understanding these distinctions helps you determine the best protection strategy:
- Light Frost (32°F to 38°F / 0°C to 3°C)
Light frosts rarely damage established plants like kale or spinach and can even enhance the flavor of cool-season crops. Young seedlings, however, benefit from protection such as row covers or old sheets. - Heavy Frost or Light Freeze (29°F to 32°F / -2°C to 0°C)
At this level, cool-season crops may survive, but sensitive plants like potatoes can suffer damage. Covering plants with cloches or row covers can effectively protect them. - Damaging Freeze (25°F to 28°F / -4°C to -2°C)
Temperatures in this range can damage or kill crops like tomatoes and harm fruit tree blossoms. Protection is crucial for preventing significant losses. - Severe Freeze (below 24°F / -4°C)
This extreme frost can destroy fruit trees and unprotected seedlings. Using double layers of protection, such as combining cloches and cloth covers, can significantly reduce damage.
3 Ways to Insulate Your Plants
1. Use Plastic Jug Cloches for Individual Plants
Plastic jugs make excellent, inexpensive cloches for widely spaced plants like kale, lettuce, or broccoli. Simply cut the bottom off a gallon jug and place it over your plant. Secure it in the ground with a stick through the handle, ensuring it stays in place. For added protection during harsh weather, you can cover the jug with an old blanket or towel. This simple method can increase the temperature around your plants by several degrees, keeping them safe during light frosts or freezes.
2. Protect Crops with a Row Cover Tunnel
A row cover tunnel is a fantastic way to protect a whole row of vegetables, such as broccoli, cabbage, or lettuce. These tunnels trap heat during the day and provide an extra layer of protection against cold nights. To build one, secure a lightweight fabric cover over hoops or stakes, anchoring the edges with boards or rocks to prevent wind from blowing it away. During extreme weather events, adding small flowerpots or boxes inside the tunnel can provide additional warmth and shielding from heavy snow or freezing temperatures.
3. Insulate with Warming Blankets
Old blankets or bedspreads can add significant warmth to your plants, especially during severe cold spells. By placing them over hoops or stakes, you can prevent direct contact with the plants while keeping them insulated. A well-placed blanket can raise the temperature around your plants by up to 10°F (5°C), offering protection from hard freezes. Even in wet weather, this method is effective at keeping your plants cozy and protected.
Conclusion
Spring frosts are an inevitable part of the gardening season, but with the right techniques, you can minimize their impact and protect your crops. Whether using homemade cloches from recycled plastic jugs, covering your garden with row tunnels, or insulating plants with old blankets, these strategies will help your garden thrive through chilly spring nights. By preparing in advance, you’ll give your plants the best chance to flourish, even in unpredictable weather.