Row Cover Roundup

By Greg and Pat Williams

Seasons of the Garden

Row Cover Roundup
Grow rice, pinch peppers and trap bees.

More and more gardeners are setting row covers over their spring plantings to protect them against frost, to boost growing temperatures and even to keep out insects. If you use row covers unwisely, though; you can actually reduce garden productivity. For example, young tomato plants exposed to just a few hours of 95 °F temperatures (not uncommon under plastic on a sunny day) set fruit poorly later on.

Timing—deciding when to put on and remove the plant protectors—can have a big effect on success, but the most important factor is picking the correct material and design for your situation. That's not easy—there are literally dozens of types available.

Writing in American Vegetable Grower, Dr. Doug Sanders, Extension Horticultural Specialist at North Carolina State University, sized up the benefits and drawbacks of the major types of row covers.

Clear polyethylene, hooped: cheap and widely available; quite warm (can become too hot in some cases); labor-intensive installation and removal; poor frost protection.

Clear polyethylene, floating: quite warm (can become too hot in some cases); less labor-intensive than hoop designs; poor frost protection.

Clear polyethylene with slits, hooped or floating: reduced chance of overheating; hard to install.

Perforated clear polyethylene, hooped or floating: more chance of overheating than polyethylene with slits, but easier to install.

Spunbonded polyester, floating: easy installation and removal; low chance of overheating; can be abrasive to plants; expensive.

Spunbonded polypropylene, floating: low chance of overheating; good frost protection; not very abrasive to plants; expensive.

Extruded polypropylene, floating: avail able in very wide widths; easy to install; tears spread easily; poor frost protection.

Photodegradable polyethylene: available with or without vents; no removal necessary; can degrade too slowly or too quickly, depending on weather conditions.

Research Briefs

Grow rice on dry land! M-101 upland rice, being introduced this year by the Southern Exposure Seed Exchange (P.O. Box 158, North Garden, VA 22959; catalogue $3), can be grown without flooding the soil. In fact, it's said to require less water than corn. Upland rice has shown no serious insect or disease problems and has been grown from Florida to Albany, New York. Yields average about five pounds of grain per 100 square feet. The hitch? You have to dehusk the grain (SSE is researching small-scale dehusking methods).

A quick trick. A Danish horticulturist reports that clear plastic mulch can speed germination of direct-seeded onions, leeks, carrots and parsley. But be sure to remove the mulch soon after the seedlings emerge so they don't get scorched.

Bells without blooms. University of Massachusetts researchers report that removing all flowers that form on bell pepper plants early in the growing season increases total fruit yields. In fact, the highest yields came from plants that were kept completely de flowered until July 30!

A rabbit-resistant lettuce. New Isbell buttercrunch lettuce is reportedly more resistant to rabbit predation than either Bibb or Boston varieties—as well as being better yielding and more cold hardy. Contact J.D. Norton, Alabama Agricultural Experiment Station, Auburn University, AL 36849, for information on availability.

African bee trapping. The dreaded Africanized (so-called killer) bees are still migrating up from Central America and are due to arrive in southern Texas either this year or the next. Can they be contained? The best hope now is to set out lots of inexpensive swarm traps baited with a highly effective pheromone lure.

Suds for slugs. Most gardeners know that beer set in ground-level saucers lures slugs to fall in and drown. Colorado State entomologist Whitney Cranshaw has been running trials to determine which beer works best. The winner? Kingsbury Malt Beverage—a nonalcoholic (but yeasty) brew!

Gleanings

Fragrant fake apple traps from Ladd Research Industries, P.O. Box 1005, Burlington, VT 05401, may well control back-yard apple maggot problems .... The EPA-approved protectants Frost Free 50E and Golden Frost Free (Plant Products Corp., P.O. Box 1149, Vero Beach, FL 32961) are reputedly extremely efective if applied about eight hours before a predicted frost . . . . Single copies of the booklet "Gardening in Raised Beds and Containers for the Elderly and Physically Handicapped" are free from Dr. Diane Relf, Dept. of Horticulture, Virginia Polytechnic Institute, Blacksburg, VA 24061 . . . . $1.50 sent to the Indoor Citrus & Rare Fruit Society (176 Coronado Ave., Los Altos, CA 94022) will get you a good 10-page resource listing of unusual warm-climate fruits suitable for hobby growing (ask for issue 23 of the society's newsletter).

Greg and Pat Williams raise most of their food on a small farm and publish HortIdeas, a fine newsletter on gardening research and products ($15 a year from G. & P. Williams, Rt. 1, Box 302, Gravel Switch, KY 40328).