4 Thing to Know for Winter Gardening and Dealing with Frost

1. What is the difference between a frost, a freeze, and a hard freeze?

   1. A frost advisory from the national weather service means the temperature is expected to drop between 36 and 33 degrees. The formation of ice crystals on the ground and on your plants is likely.

   2. A freeze warning comes when temperatures are expected to drop below 33 degrees and wind speeds are above 5mph, bringing significant cold air and wind.

   3. A hard freeze occurs when temperatures are lower than 28 degrees. While some plants may be able to tolerate a frost, many will not make it during a hard freeze.

2. What plants are sensitive during the winter?

   1. All plants have a "hardiness zone" and plants that are hardy to warmer zones should be protected. Charleston is in zone 9a, meaning plants that are hardy here can withstand 20-25 degrees. However, many of our favorite tropicals and container gardening plants are only hardy in zones warmer than us and will not be happy in freezing temperatures. Check out the map below for more details!

   2. 

      Plants that need protection include: tropicals like banana trees, elephant ears, hibiscus, citrus, cordylines, bromeliads, duranta, and crotons. Other sensitive plants include: boston ferns, pencil cactus, farfugium, and "cool season" annuals like dianthus, begonias, snap dragons, dichondra and more. While many of our cool season annuals can handle a brief frost, they may sustain damage during a prolonged hard freeze.

3. How should I protect my plants?

   1. Your plants need insulation to keep the roots warm. Use mulch or leaves around the base of sensitive plants.

   2. Ensure your plants (and the material used for insulation) are watered thoroughly.

   3. When possible, bring potted plant inside or group container plants together and closer to your house for warmth.

   4. Use sheets, frost clothes, or other linens to cover plant material. Ensure the material is secured close to the ground for maximum effectiveness.

4. What are the signs of frost damage?

   1. Damage from a frost or freeze may not show up immediately. The cold air, water, and ice around your plant's leaves is not killing the plant, but the water inside the plant's cells will freeze and form ice crystals, causing the cells to rupture.

   2. Ruptured cells lead to: browned or blackened leaves, wilting or droopy leaves, or scorch marks on leaves.

   3. Some plants are cold hardy, but the blooms will receive damage.

   4. The more hours or days below 33 degrees, the more chance of widespread damage.

We hope this guide helps you navigate the winter season!