Row Covers; Gardening Guidebook for Spokane, Washington ~ Master Gardeners of Spokane, Washington State University ~ For more information, Please see websites below: ` Organic Edible Schoolyards & Gardening with Children = http://scribd.com/doc/239851214 ~ ` Double Food Production from your School Garden with Organic Tech = http://scribd.com/doc/239851079 ~ ` Free School Gardening Art Posters = http://scribd.com/doc/239851159 ~ ` Increase Food Production with Companion Planting in your School Garden = http://scribd.com/doc/239851159 ~ ` Healthy Foods Dramatically Improves Student Academic Success = http://scribd.com/doc/239851348 ~ ` City Chickens for your Organic School Garden = http://scribd.com/doc/239850440 ~ ` Huerto Ecológico, Tecnologías Sostenibles, Agricultura Organica http://scribd.com/doc/239850233 ` Simple Square Foot Gardening for Schools - Teacher Guide = http://scribd.com/doc/239851110

1. 222 N Havana
Spokane WA 99202
(509) 477-2181
http://spokane-county.wsu.edu/spokane/eastside/
mastergardener@spokanecounty.org
C187
ROW COVERS
Row covers have been used for many years in Europe, Asia and Israel and their use is gaining
popularity in the U.S. You may have used the technology yourself when covering your crops with
plastic for frost protection or weed control. These days, more advanced materials such as spun-bonded
polypropylene-cotton and polyvinyl alcohol (PVA) are available, providing insect control and
enhanced growing environments for vegetables and ornamental plants. Some lightweight materials,
referred to as ‘floating row covers’, are laid directly on the crop and lift as the plant grows, while other
materials require hoops to hold the fabric off the plants. The type of plants, your desired benefit and
your budget should all be considered when selecting the row cover material.
A number of benefits are experienced from the use of row covers:
• Extended Growing Season - Crops may be planted 1-2 weeks earlier than usual and the
season can be equally extended in the fall. The greenhouse effect warms the soil and speeds up
germination, root growth and nutrient uptake.
• Frost Protection - The amount of frost protection provided varies by the material used. For
better frost protection, heavier weight materials are used. Hoops are needed to support the
heavier fabric since plant material touching the cover material could be damaged by frost.
• Pest Protection - A floating row cover placed over seedlings before they emerge prevents pests
like aphids, loopers, beetles, root maggots, cabbage worms, cabbage maggots, leafhoppers and
whiteflies from reaching tender seedlings. It is important that the edges of the row cover remain
sealed by either burying or weighting the edges.
• Moisture Retention - Rather than evaporating away, water condenses on the underside of the
row cover and returns to the soil. Protection from the wind also aids the plant in retaining
moisture. It is important that the row cover be securely fastened so the material won’t flap in
the wind and damage the plants.
There are some other details that should be considered when using row covers.
• The environment under the cover is pretty ‘cozy’ for insects, so it is important that all
transplants that are to be covered are free of insects at transplanting. For added protection,
placing sticky traps under the cover will help capture any uninvited pests.
Cooperating Agencies: Washington State University, U.S. Department of Agriculture, and Spokane County.
WSU Extension programs and policies are consistent with federal and state laws and regulation on
nondiscrimination regarding race, color, gender, national origin, religion, age, disability, and sexual orientation.
Evidence of noncompliance may be reported through your local Extension office.

2. • The covers need to be removed about a week before flowers start blooming so that pollinators
can perform their function. The row covers can be replaced after pollination but the area should
first be checked carefully for insects.
• Row covers do not work well if it snows after they are applied. The weight of the snow pushes
down the fabric, possibly breaking branches on plants.
• Out of sight, out of mind. It is easy to not check plantings under the row cover as often as one
should. Set up a schedule for looking under the covers and checking for insect presence and
weed growth.
• Watch for warnings about using row covers when air temperatures are above 80 degrees.
Despite the drawbacks, the benefits of using row covers have proven to be an important technique in
obtaining higher quality and higher yield plants.
See C185 Pest Traps for additional pest control information.
Compiled by Tonie Fitzgerald and Mark Stiltz. For more information, contact Master Gardeners at (509) 477-
2181.
Revised January 2005