Frost Protection Tips: How To Protect Plants From Frost

frost on the leaves

Question: What steps can we take for frost protection on our plants and should we use frost covers or frost blankets made for plants? Linda, Crestview, Florida

Answer: Protecting plants from frost and the damage that can occur is a regular part of landscape maintenance.

Many of us face frost on a cold, cloudless evening in the spring, fall and winter months. A good blast of cold and dusting of frost can be hazardous to the health of your plants.

Storing Heat During the Day

During the day when the sun is shining the soil and your plants will absorb and store heat from the sun. Slowly as day fades and night falls on the landscape, the soil and plants rapidly begin to lose the stored heat.

This is especially true on cold, clear nights.

specialty blanket or cover made for frost protection on plants

When cloud cover is present the clouds work as a blanket to insulate some and slow the loss of heat from the earth. On cloudless nights where the wind is calm or non-existent, no protection whatsoever will nature provide.

As a reminder – soil temperatures and plant cells may drop below the air temperature.

Frost Explained

As temperatures drop the moisture in the air will condense and turn into dew. The dew “freezes” when the air temperature hits 32° F on the surface of the plant.

Many people think the 32° degrees cause the damage. Damage at the 32° temperature will be minimal to most plants in the landscape. The plant problems come when the temperature drops so much that the cells inside the plant freeze, that is when the non-hardy plant dies.

Even is areas considered “frost free” weather conditions can occur which can bring on a frost.

Tracking Local Weather

Tracking weather from the local weather forecast is helpful, but taking the extra step to tune in with a weather radio or have your own home weather station will give more information.

Over the years I developed my own “weather calculator” for my growing operations. By tracking the weather over the years we could take the data from the agricultural weather forecast and translate it for our local “mirco-climate.”

As a point of warning… when the weather broadcast predicts a “chance of frost” take the needed precautions for protection of your garden, landscape and greenhouse.

With so pre-planning and precautions the growing season may be extended by only bringing your plants through the first frost.

Surviving the Frost – What Can You Do

Besides tracking the weather one of the first steps you can take to minimize damage to plants is to grow plants which will survive, withstand or handle a frost. “Frost Hardy Plants” can be somewhat misleading.

A light frost and a killing frost are two different animals.

Your best bet is to seek the advice of a qualified local nurseryman who can guide you in the best plants and varieties suited to your area.

Let your eyes do some talking. Look around your neighborhood to see what is established and growing well from year to year.

Plants may survive frost on the foliage but the same temps and frost may kill any flower buds. That being the case you may need to look for varieties that bloom earlier or later depending on the time of the year the frost occurs (spring or fall).

Know The Highs and Lows of Your Garden

Cold air is heaver or denser than warm and hot air, be aware low lying areas of the garden may get colder by several degrees than areas in higher spots.

Plant the more tender plant varieties on higher ground or on slopes where cold air will not settle.

You can precondition your plants and landscape to get them ready to battle the winter temperatures by stopping fertilizing in early September.

frost on the leaves

This way new foliage with soft growth will not be on the plant when the temperatures begin to drop. Older and mature leaves are tougher and in much better condition to handle and survive a frost.

When Frost Arrives – Frost Protection For Plants

When you know frost is a possibility here are a few things you can do to offer some protection for your plants.

  • Water thoroughly before nightfall. This will allow the soil to release moisture into the air during the night, around your plants, keeping the air somewhat warmer.
  • A slight gentle breeze throughout the night can stop or prevent cold air from settling near the ground. Fans can be used to move the air but take precautions to protect the fan and electrical connections from any possibility of water and the elements.

    By the way Disney World takes advantage of moving air by using forced air heaters to keep air moving and raise the temperatures in their parks when the temperatures fall.

  • Cover up before the sun goes down! When the sun goes down much of the heat stored during the day will have already been lost.

    To keep the “heat in” and have the time and ability build a frame around the plants, then cover with cardboard, plastic tarps, special plant frost protection blankets or even bed sheets can be used.

    Any type of lightweight material which can be used to make a temporary “tent.”

    Search for these specialty frost protection plant products: The Planket | Frost ProTek | FrostCare

    If time is short you can lay the material directly on the plant. This will help slow the loss of heat rising from the plant and ground.

    Always remove any covering in the morning once the “fear of frost” has passed. This will let fresh air back in and prevent overheating during the day.

  • Potted plants can experience frost damage from their roots being unprotected. If possible move plants indoors or push them altogether and cover them as well with a lightweight material.

    Consider burying them in the ground. Uncover them after possibly of frost has passed.

If frost arrives before you have taken the necessary frost protection steps and the plants experience damage do not be in a rush to cut off the damaged parts of the plant. These damaged leaves can work as somewhat of as an insulator for further damage, plus when spring comes around the plants will need pruning again anyway.

Images: ellaphotography

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