The weather this spring has been a challenge for gardeners. Temperatures in the 80s in March and April fooled some people into planting too early and the frosty temperatures over the last two weeks found them regretting their early enthusiasm.
There is nothing we can do about the overeager fruit trees, strawberries and grape vines that leafed out or flowered too early and had their tender growth killed by frost. The hope is that enough of the flower buds survived for at least a reduced crop, and that there is enough life in the grape vines to send out new leaves.
Some vegetables and flowers are tough enough to take a light frost. If you’ve already got pansies, violas or snapdragons outside, they probably did fine in the cold weather over the past couple weeks. Likewise, potatoes, peas, kohlrabi, radishes, beets, carrots, cabbage, spinach and other greens almost certainly survived unharmed.
There are other plants that are much more sensitive to cold temperatures. Before planting you should be very certain that either the last frost has occurred or that you have a plan to protect tender plants if a late frost is forecast.
Tomatoes, peppers, beans, cucumbers, eggplant, melons, squash, pumpkins, and basil will be killed or severely set back by even a light frost. Some bedding flowers can take temps hovering around 32° but others like impatiens and begonias will become a slimy mess when the temperature drops. Other tender bedding plants include ageratum, celosia, dahlia, geranium, lisianthus, nicotiana, moss rose, salvia, cleome, vinca and zinna.
What if your tender plants are in the ground and a frost is forecast? Cover them. Plastic tarps, old shower curtains, window curtains, blankets or sheets can be laid gently over rows or beds of plants. Stake the covers down or put rocks or other heavy items around the edges so they don’t blow off. If the young plants will be crushed by the weight of the cover, use wooden stakes to tent the cover a few inches above the plants, making sure the edges of the cover reach the ground. Bushel baskets or buckets can be upended over individual plants like tomatoes and peppers.
The worst damage from frost actually happens in plants when they warm back up the next morning. Frost freezes the water inside the plant’s cells, which damages the cell walls. When the warmth of the morning sun hits the plants, they defrost rapidly and the cell walls rupture.
There is a way you can try to save the plants by preventing the rapid defrosting. Lightly misting or spraying the foliage with water before the sun reaches it will help the plant to thaw without the shock of sudden warmth.
Even hardy plants that are lightly touched by frost may take awhile to recover. Make sure they are watered regularly, but know that frozen or damaged roots don’t take up water as easily, so it’s easy to overwater and drown a recovering plant.
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