Row covers can protect plants from cold, critters

KENNEWICK -- Have you ever seen white fabric covering someone's vegetable garden and wondered what it was all about?

Row covers made out of synthetic fabric have been around for a long time, but during the past 15 years they have become much more accessible to gardeners.

Reemay, Grow Guard and Agribon are some of the brand names of these polyester or polypropylene spun-bonded and woven fabrics.

Depending on the type and brand of row cover fabric, it can be used to provide protection from frost and wind and even to exclude certain pests. Most of the newer fabrics are UV stabilized so they can be used for several years. The fabrics are also porous, transmitting water and light. The lightest weight fabrics transmit as much as 75 percent to 90 percent of light, allowing good plant growth beneath them.

Because row cover fabric transmits sunlight, the soil underneath warms up during the day. At night, the fabric slows heat loss from the soil, allowing gardeners to plant one to two weeks earlier in the spring.

Row covers aren't going to protect tender plants from severely cold temperatures, but they will protect them from temperatures several degrees below freezing.

Each brand of fabric is rated for different amounts of frost protection, with lighter weight materials only providing a few degrees of protection and others, such as Frost Blanket, protecting plants down to 24 to 26 degrees.

Lightweight fabrics, often called "floating row covers," have become increasingly popular in recent years because of the protection they provide from certain insects and birds. If applied correctly, row covers can exclude insect pests such as leaf miners, aphids and flea beetles while still allowing plants to grow beneath. They are the best option when trying to control leaf miners in spinach and beets.

Row cover fabric comes in varying lengths and a standard 72-inch width for use on three to four foot wide garden beds. You can find row cover fabric at local nurseries or through mail-order supply companies.

(Territorial Seed Company offers four brands at

You also can purchase pegs, staples or clamps that are available for securing the fabric.

However, digging a continuous furrow along the edge of the bed and burying the fabric edges is the best way to secure your row covers in our wind prone region.

Install the fabric on a calm day, as a strong breeze makes the process impossible.

Place one of the long edges in the open furrow, securing the fabric using staples and pulling the fabric lengthwise as you go to remove any folds.

Then secure the fabric along the opposite side. The material should be loose, not taught, to allow room for plant growth.

Secure both ends in the same way.

Lastly, fill in with soil. Securing the fabric in this way keeps leaf miner insects and birds out, as well as preventing the wind from lifting up the fabric.

Some gardeners like to use 2-by-4 lumber to anchor their covers on one side so they can open the bed to check on their plants and to harvest leafy greens. It also allows them access to manage soil moisture and weeds. (Be aware that weeds are able to grow very well under the row cover fabric.)

Row cover fabrics are a handy way to provide some frost protection to your garden plants in the spring and a chemical-free way to keep out certain unwanted pests, such as leaf miners and quail. You might want to give them a try.

* Marianne C. Ophardt is a horticulturist for the Washington State University Benton County Extension.