Preparing for the frost

We had a cold spring which resulted in a slow season. While a few plants grew fast many are behind where they normally are at this time of year.

We had a cold spring which resulted in a slow season. While a few plants grew fast many are behind where they normally are at this time of year.

This can be seen in the garden as well as in local flower shows. It doesn’t mean that there are less flowers and vegetables to view, it just means that there are different ones for the time of year.

A late season also means that many of the vegetables are not maturing as fast as other years. As September approaches, plants are once again in danger of being damaged or killed by frost. Protecting tender plants during a cold period in the early fall usually ensures that the plants have time to mature when the weather once again becomes warm.

It is harder and takes more material to cover plants in the fall as the plants are larger. Sheets and light tarps work to protect plants from a light frost. Doubling the covering is needed if the temperatures get lower. The materials block the sunlight and need to be removed each day to ensure the plants get sunlight.

Plastic can be used successfully in combination with another material such as cloth, tarp or newspaper. Make sure that the plastic does not come in contact with any plant. Plants that touch the plastic are more likely to freeze than plants that are not covered.

Floating row covers, or polyspun cloth is made of a lightweight woven or spun-bonded synthetic material that allows the sunlight and rain to penetrate but keeps out up to -5C of frost. This cloth can be put in place and left until the growing season is over.

When covering plants with any cloth make sure that the cloth does not have holes and is secured to the ground. The plants must be fully contained in the covering. Holes allow the cold air to enter.

The first frost often occurs after a cold rainy period. If the clouds clear during the night the warm air disappears into the atmosphere leaving the earth colder.

On rainy nights plants survive with little or no frost as they are protected by the moisture that coats their leaves. The water insolates the plants against the cold.

The same effect can be created by wetting the garden with a sprinkler or hand held spray in the early morning hours. All parts of the plants must be dripping with water to protect the plants.

Greenhouses and cold frames keep the out minor frosts but they too can be kept viable longer. A heater is the obvious choice except it becomes very expensive. A fan that circulates the air still uses electricity but it isn’t as expensive as heat.

Moving air from wind or a fan will not let the frost settle and the plants will not freeze.

Pots and baskets that are close to the building often escape the frost.

To be safe, bringing pots and baskets inside or into a garage can ensure colorful planters until October.

With a little care these plants can add color to the otherwise bleak landscape.

Another alternative would be to replace the tender plants with hardier ones.

Fresh mums and pansies are in the stores. These plants continue to perform through light frost and occasionally into snow.

Spending time to keep plants alive though the first few frosts is usually worth the effort as a frost can be followed by two or three weeks of warm weather.

Linda Tomlinson is a horticulturalist and educator living in Rocky Mountain House. You can contact her at