A Security Blanket for Plants

Floating row covers help protect plants from the cold and pests. (By Paul J. Milette -- Palm Beach Post/zuma Press)

Meet the Kleenex of the horticultural world. It's called Reemay. Developed by DuPont in the 1960s, Reemay is a white spunbonded polyester fabric that is spread over plants as protection against cold and pests. Intentionally nonabsorbent (it's also used as the top, or "acquisition," layer in disposable diapers), it is porous and extremely lightweight. As with Kleenex -- or Saran Wrap or Band-Aids -- Reemay succeeded so well as a pioneer product that its name became generic. There are now other brands, such as Agronet and Agribon, but most gardeners call all of them Reemay.

A name was needed for use by rival manufacturers -- and garden writers trying to avoid bias -- so the term "floating row cover" was born. It's a good one, because that's exactly what this fabric is. It floats weightlessly above the crops, letting in water, light, air and liquid fertilizer. It rarely needs to be removed. A length of it (usually five to six feet wide) is unrolled over a garden row like a long, white tablecloth, then anchored at the ends and sides.

This month, as the nights get colder and many fall crops are still in the ground, I've covered rows of baby turnips, which are crisp, sweet and tender now and topped with excellent greens. At night the covers hold in some of the soil's heat, keeping the plants as much as seven degrees warmer than they would otherwise be and thus extending the season. Earlier this fall I used covers to drape over basil and other tender crops on nights when frost was forecast.

When winter settles in for good, I'll remove the covers, brush off the dead maple leaves and carefully roll them up for storage. (Sharp objects and brisk tugs can tear the covers, but, handled gently, they can be reused.) We are laying some over beds inside our unheated greenhouse to add another layer of protection for fresh winter carrots, turnips and radishes, as well as numerous leafy crops. Come spring, I'll use them to cover early outdoor plantings. They'll lend two or three degrees of warmth -- less than in fall because the cold spring earth radiates back little heat.

I'll also have covers on hand for crops vulnerable to pests. By using compost and other good garden practices to avoid pests, I'm hopeful there won't be any, especially because I rotate my crops. But for insects that travel, such as potato beetles, cucumber beetles and the flea beetles that plague spring arugula, floating row covers are a great barrier. They'll keep the root maggot fly from laying eggs on brassicas such as broccoli and cabbage.

Rotating each crop (or its relatives) to a new part of the garden each year is essential with these covers. Otherwise, larvae might emerge to find a perfect biosphere, stocked with their favorite diet and shielded from predators. It's wise to make sure that no creatures you find under the covers are those that will chew on, or lay eggs on, your crop. You also must remove the covers periodically to weed and harvest and to give pollinators such as bees access to fruiting vegetables, including squash, cucumbers and peppers. The covers, available from many catalogues, come in different weights. The lightest admit the most sun; the heaviest give the most frost protection.

The only tricky thing is the "floating" part. On one hand, this is their claim to fame. Lying directly on a bed, with enough slack, these covers simply rise with the plants as they grow. But they also might float off the bed in a heavy wind. Gardeners have their favorite anchoring systems: rocks, bricks, boards or hairpin-shaped metal prongs that staple the fabric to the earth. Some bury the edges in the soil -- a secure, though inconvenient, way to keep insects from crawling in. For a while I used lengths of iron rebar, which were easy to lay down -- unless a strong wind was blowing. Just when I'd secured fabric beneath one end it would escape from the other. Recently my husband found that sandbags were the perfect solution.

In our windy garden, the fabric flaps against the plants, abrading them, so we support our covers with wire wickets. These can be purchased, but it's simple to make your own from lengths of 9-gauge wire. Bend them like croquet wickets and sink an end into each side of the bed, spacing them every four feet. The perfect system! Or nearly so.

The only complaint I have about the covers is their looks. Expanses of opaque white interfere with that essential eyeball-to-plant connection on which a good gardener depends. Too hastily bunched and stored, the row covers make garden sheds unkempt, like so much modern detritus for which we have uses, if not love. But they're here to stay. Like Kleenex.