Master Gardeners: Saving your garden from a Spring cold snap

Published 8:06 am Saturday, January 16, 2021

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By Sheri Bethard

Orange County Master Gardeners Assn.

During most years by the end of February into the middle of March, we are finished with winter. Some years it seems to happen earlier. On those days when the temperatures are in the high 60’s and even low 70’s you are anxious to get out and work in your garden, planting seeds and your seedlings. This is all good and great but what should you do if a sudden cold snap comes roaring thru? I have seen it get down in the low 30’s well into March. I wanted to share some steps you can do to prepare for these cold fronts.

First, let me explain what the various temperatures can do to your plants. If we have a light freeze (temps. 29-32F. degrees) this will kill some annuals and vegetables and could cause damage to hardier plants. A moderate freeze (25-28F. degrees) will kill hardier annuals and vegetables along with many perennials and deciduous shrubs will develop wet, mushy or blackened leaves that will eventually fall off.  Then a hard freeze (24F. degrees and below) annuals and vegetable crops are killed outright, perennials have extensive damage on exposed foliage, trees and shrubs often lose emerging leaves and flowers.

So, the question is what do I do to help prevent loss of my plants? Here are five things you can do to help your plants make it thru the cold times.

  1. Water the soil prior to the cold snap. Damp soil holds daytime heat and keeps the air above warmer by about 5 degrees. Do this the morning before the freeze. But, do not wet the leaves as they could freeze faster.
  2. Cover tender plants. A great thing I discovered several years ago is Frost Cloth. They have better insulating properties than plastic. Place stakes around the plant to keep the cloth from touching if possible. This will help leave a zone of a little warmer air around the plant. I have been using frost cloths on my large plants which are too tall for my greenhouse the past couple of years and have not had any damage to them even when the temperatures were in the 20’s. Other items you can use are cloches, buckets, milk jugs with the bottoms cut out or even old aquariums which create a mini greenhouse. Remove these items the next day so when the sun comes out, they will not “be cooked”.

When using frost cloth or any other woven fabrics be sure the material goes all the way to the ground as the heat from the ground will rise into your tented plant and not escape.

  1. Capture radiant heat by filling jugs with water around your plants during the day. If you paint the jugs black, more heat will be absorbed. Place as close to the plants as possible.
  2. Wait until spring to add mulch as the warmth from the soil will radiate upwards toward your plants. Mowing grass shorter around plants will expose more soil to heat up also. If you put mulch down in the fall, leave it as long as possible. Mulch keeps the ground cooler and will keep plants from breaking dormancy too soon.
  3. Don’t clean up too early. The prior years growth helps insulate the crown and stems. Wait until new leaves appear before pruning. If pruned too early, this would encourage new growth which could be damaged by the unexpected cold snap.

Good Luck and don’t be too antsy to get started with spring gardening with the nice days we had last week. As you can the cold is upon us again.


For your horticultural questions, please call our Hot-Line 409 882-7010, Tuesday and Thursdays from 10 a.m. – 2 p.m. or email More information can be found on our website or our Facebook group Orange County Texas Master Gardeners in the files section.