When the temperature plummets and frosts are common, gardeners need to have taken steps to protect non-hardy plants growing in their gardens but how cold is too cold for plants?
Different plants are affected by frost and can fail at different temperatures. That is why most plants are given a hardiness rating. It is not widely known that some plants produce special hormones that keep them from freezing, and these plants can survive colder weather than plants which produce less of this hormone. Although a plant may lose all its foliage during a freeze, and some can regrow from the stems or even the roots. So, while the leaves cannot survive freezing temperatures, other parts of the plant can.
So, what is the most effective way of protecting those less-hardy plants in our gardens? If you are only expecting a light freeze, you may be able to protect plants in a freeze by simply covering them with a sheet or a blanket. This acts as insulation, keeping warm air from the ground around the plant. The warmth may be enough to keep a plant from freezing during a short cold snap. For added protection when you protect plants in a freeze, you can place plastic over the sheets or blankets to help keep warmth in.