Put Weeds, Pests Under Cover
Designed to get down and dirty, garden fabrics may never make an appearance on a Paris fashion runway, but they may make gardening a whole lot easier.
Judging from the gardeners we talked to, some kind of garden fabric is probably in your future, especially if you grow edibles. Different kinds of fabrics can protect from pests, sun and weeds and make seeds a snap to germinate or bring in the earliest melons or tomatoes on the block.
The most exciting are the new flyweight “floating row covers” that look like gauze but are made of spun-bonded polypropylene, polyester or other woven plastics. Designed as “season extenders,” they raise the temperature underneath by 10 degrees or more, but it was also discovered, almost by accident, that they exclude pests, even as tiny as an aphid or flea beetle.
They transmit almost 100% of the sunlight hitting them, and they are so light that they can be laid directly on top of plants, which simply push them up as they grow. You can water right through the fabric, by hand or with a sprinkler.
In San Marcos, market gardener Richard Borevitz uses floating row covers to raise the temperature enough to bring in early crops of cucumbers, squash and melons for his Gourmet Gardens roadside stand.
Mike Heuer of Harmony Farm Supply (P.O. Box 460, Graton, CA 95444, [707] 823-9125), one mail-order source of garden fabrics, cautioned that there’s a downside to this warming ability. “You can really crisp a crop,” he said, if daytime temperatures go above 90 degrees, so floating row covers are best used during the cool months, from fall through spring.
Gardeners on the East Coast, where the row covers were invented, are finding them indispensable. Kip Andersen, the gardener for public television’s “The Victory Garden,” said you simply can’t grow cucumbers in Massachusetts without a floating row cover, and it has nothing to do with the short growing season.
Cucumber beetles transmit a wilt disease that kills plants before they can set fruit. Covering the plants with a row cover until they begin to flower excludes the beetles, and plants survive long enough to produce good crops.
California farmers use them in a similar way in the Central Valley for fall cucurbit crops (cucumbers, melons and squash) that get mosaic and other diseases, said Visalia farm advisor Manuel Jimenez. Transmitted by aphids and other insects, these diseases can ruin cucurbits, but row covers keep the disease-carrying critters out, if used from the start. When plants begin to flower, the covers should be removed so pollinating insects can get to the flowers.
The covers even keep slugs and snails away from tender new plants and they help seeds germinate by holding in a little moisture and raising the temperature. A few adventuresome gardeners have found them the best way to start hard-to-germinate carrot seed.
One is Joyce Gemmell, in the Master Gardener program in El Cajon. “Floating row covers are unbelievable on carrots and salad greens, wonderful on cole crops,” she said. “I’d never garden without them.”
She lays floating row covers directly on top of seed beds for carrots and salad greens, like the mesclun mixes, and watches the plants push them up as they sprout and grow. She simply spreads them loosely over the seeds or transplants and buries the edges in the soil.
For other crops she makes tunnels of the row covers, by draping them over wire hoops made from 6-feet lengths of 9-gauge wire (hoops can also be made of half-inch PVC pipe). The hoops are spaced about four feet apart and are all connected at the tops with light nylon rope. To keep the wind from whipping them around, she uses spring-type clothespins to secure the fabric to the rope. The edges touching the ground are stapled to 1-by-1-inch sticks so they are easy to lift up when working with the plants underneath.
Gemmell uses the tunnels in fall and winter for cole crops like broccoli and cauliflower, for which they provide extra warmth and protection against cabbage looper and snails.
In spring she starts tomatoes, eggplant and peppers underneath, removing the tunnels when plants hit the top. The tunnels add heat and exclude even the tiniest pests, such as flea beetles, which can make young eggplant look like it was blasted by a shotgun.
Borevitz cautions to “plant and cover immediately.” Otherwise you may trap pests inside.
Most row covers last several years if you’re careful with them. Brands such as Reemay, Tufbelll and Agrofabric are easy to find in mail-order catalogs in lengths short enough for home gardens.
Prepare to be amazed at the growth under the row cover. “It’s truly phenomenal,” says the Victory Garden’s Andersen. With no pests and warm temperatures, everything grows like Jack’s beanstalk.
Although row covers are the big news, there are other useful fabrics made especially for the garden:
Shade cloth
Woven fabrics that shade the garden have been used by some gardeners for years, on structures over fuchsias or cymbidiums for instance. You’ve seen them at nurseries where they protect the shade-loving plants.
Shade fabrics have been getting better and better through the years. They are now able to stand up to the sun for more than a few years and are stronger, so they don’t easily tear. You can find them in various densities, from light shade to quite dark, at nurseries and in catalogs.
In the garden, they can be attached to overhead structures to shade large areas or used on hoops in the vegetable garden to grow crops that like cooler temperatures in summer.
One catalog suggests 80% shade for shade-loving ornamental plants but only 47% for lettuce, spinach and other crops that need some summer cooling in really hot areas.
Weed barriers
Woven fabrics that keep weeds from growing undoubtedly have their uses in Southern California but, so far, most people who have tried find them somewhat less than amazing.
People on the East Coast use them extensively, rolling out the fabrics over prepared soil, cutting Xs and planting right through them, covering the barrier with a mulch to make it presentable and protect it from the sun.
But most East Coast weeds are perennials, which get trapped underneath. Heuer and others say annual weeds find a way to sprout and grow in the mulch above the barrier. And, Heuer adds, “They won’t stop Bermuda grass.”
After a few years, the barriers “float” to the surface and begin to degrade. Picking up the old barrier and laying down a new one is difficult and messy.
Heuer thinks they’re “fairly effective” if they are pinned to the ground and a good thick mulch put on top. A variety of special pins is sold for this purpose and mulches--gravel or chips from a tree service--should be at least 3 inches thick. Chunky bark probably makes the worst mulch on top of a weed barrier.
For the experimenter, there are many new kinds of weed barriers that are worth trying. One is called Ewemulch (from the Natural Gardening Co., 217 San Anselmo Ave., San Anselmo, CA 94960, [707] 766-9303). It’s a natural, light-brown, permeable wool blanket, suitable for short-term uses because it is biodegradable.
Bird netting
Nylon bird netting is the ultimate way to keep birds and other larger pests away from fruit. Because it can be hard to get on and off, some gardeners have actually built large aviary-like structures that cover fruit trees or berry bushes.
It is a necessity over beds of strawberries, and here you can simply drape it over the plants.
Some gardeners have also found that draping it over newly prepared or planted beds prevents cats from using that nice loose soil as an Olympic-size litter box.
