Protecting Your Garden From the Cold

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This weekend we are forecasted to experience nighttime lows below 40 degrees. These temperatures are uncharacteristic for this time of year, and while they are not below freezing, they can cause serious damage to vegetable gardens because of their timing. 

Early summer gardens often experience low temperatures around 40 degrees; however, they are usually in early April, when the majority of the summer vegetables that are planted are pea and bean seeds. Seeds are less susceptible to short periods of cold weather, as they are protected by the warmth of the soil. What makes the cold weather in early May more dangerous to our gardens is that our seeds have germinated and emerged. Newly emerged seedlings and newly planted transplants are especially susceptible to the cold because there aren’t protected by the soil. With that in mind, there are things that we can do to protect our plants.

Planting/Transplanting

The first way we can protect our plants is by waiting until warmer weather has returned before planting seeds or transplants. While this might not fit into our garden schedule, warmer temperatures will help with seed germination and transplant adaptation. The ideal forecast for planting is warm temperatures with low wind and rain for a 4-5 day period. We are forecasted to have these conditions, for the first time this planting season by early next week, so wait until then if possible.

forecast image

Container Vegetables

Vegetables grown in containers are more susceptible to cold temperatures than those grown in normal soil conditions because all of the soil is above-ground and exposed, rather than just the soil at the surface. The best way to protect these plants is to move them indoors overnight. Once the sun has come up the next morning, the temperatures should be warm enough to move the plants outside. If this is not possible because of the size of the plants or the pot, you can wrap the outside of the container with an old towel or blanket to keep in some of the heat. You can also keep in some of the heat by covering the plants with a plastic container or cloth, just be sure that the covering isn’t touching the plants.

wrapped plant

In-ground Gardens

Both in-ground and raised bed style gardens need protection from the cold and face different challenges than container gardens. The main challenges are that the vegetables cannot be moved, and the quantity of plants makes them difficult to cover with plastic containers. If possible, cover plants with fabric or plastic row covers. Row cover examples can be found online, but should not touch the plant, and should be large enough to cover the plant and go to the ground. 

plants with cover over rows

If your plot is too large to be covered, one thing that will help is watering the soil near your plants. This seems counterintuitive, but the soil is warm and will prevent the water from freezing. Adding water to the soil helps to fill natural air pockets in the soil that are quicker to cool than the water. The best time to water the soil is in the afternoon before the cool temperatures are forecasted. This will allow time for the water to spread and will let any water sprayed on the plant time to dry or runoff.

For any additional gardening questions, contact Adam Formella at 252-232-2262 or email ajformel@ncsu.edu. If you are interested in seeing how these and many more gardening tips are applied to a “real-world” garden, check out our new gardening series “This Week in the Garden” where we post weekly update videos and articles.