Frost protection of 2 to 4 degrees F is afforded by the covers, but the biggest benefit is growth enhancement provided by the daily increments of solar heating. Daytime temperatures might be excessive under the cover if ambient temperatures are above 90 degrees F. Under those conditions, partial removal of the cover might be necessary, especially for tomatoes and peppers that have open blossoms. In southern regions Insolar is recommended. This cover has a white pigment to reduce solar transmission which reduces the temperature under the cover.

A newer high-density poly tunnel is now available at a lower cost. This 0.5-mil plastic, which diffuses the light, is not as visually clear as the regular 1.1-mil low-density poly; but studies have shown that light transmission and crop development are almost identical with both covers (see graph).

Wire for Hoops

Number 10 gauge Smooth Galvanized Steel wire is packaged in bundles of 100. Wires are 76" long and can be inserted 6" into the soil at each end to form a support hoop that is 16" - 18" high at the center. Wires should be spaced 5' to 8' apart (see sketch below).

Advantages of slitted/perforated row covers:

• Outdoor crops may be planted about 10 days earlier than normal
• Highest heat retention with clear perforated covers and slitted covers
• Prevention of excessive heat with Insolar
• Earlier maturity and higher yields
• No manual ventilation necessary
• Excellent for tomatoes, pepper, cucumbers, melons, and many other crops

1. Space hoops about 4 feet apart to prevent sagging of the covers.
2. Apply covers on a calm day.
3. Apply the cover taut and secure the edges with soil.
4. Machines are available for hoop and cover installation.
5. To prevent weed growth under the cover, install the cover right along the edges of the black plastic mulch.

• Vegetables -- warm season and cool season crops that are transplanted
• Small fruits -- strawberries in matted row
• Cut flowers

The results from the use of slitted or perforated row covers on various crops will vary, but in general all crops will benefit. The primary precaution is to provide extra ventilation when there are daytime spikes in temperature or use Insolar. Drip irrigation and mulch are recommended as part of the growing system.

1. Kohm, P. C. and H.C. Wien. 1983. New tunnel materials for early vegetable production in New York State. Proc. Natl. Agr. Plastics Cong.17:31-36.
2. Wells, Otho S. 1996. Row cover and high tunnel growing systems in the United States. HortTechnology 6(3):172-176.
3. Plastics website: http://www.plasticulture.org