By Adrian Higgins
Thursday, May 3, 2007
As a kid in Texas, Virginia Harmon noticed the trees and shrubs that grew downwind from her grandfather's cattle feed mill. Alfalfa meal and other goodies being processed for the steers drifted to those plants, and it turned out that the nutrients were good for them, too. They grew sturdier than the same plants elsewhere, and when the summer turned hot and dry the difference in their health and vigor became even more pronounced.
Not surprisingly, the child who observed plants so closely would grow up to become a professional: She's a gardener at the U.S. Botanic Garden's Bartholdi Park. Predictably, too, she's a big believer in feeding plants with organic nutrients and over the years has developed a recipe that she calls nutri-mix.
Before we share its secrets, let's explain a few basics. Compost made from animal manure contains low levels of nutrients. But compost is not so much a feed as a soil conditioner; used as a soil amendment or as a top dressing, it feeds soil microbes that act as helpers to plants. Plants grown with compost typically are stronger and healthier than those without it, and scientists have shown compost-dressed plants need less fertilizing because the bacteria and fungi allow the roots to feed more efficiently.
But composting is a laborious process, and most gardeners, including me, never have enough finished, screened product on hand, especially in the spring, when plants are growing and need feeding.
Spreading your own compost "is probably the best thing you can do, but the next best is to buy organic fertilizers," said Paul Sachs, founder of North Country Organics, an organic feed manufacturer and supplier in Bradford, Vt.
As consumers have been drawn to organics in recent years, an enormous market for them has developed. Unlike petroleum-based varieties, organic fertilizers build the soil and are gentler in their effect, their advocates say.
Branded, pre-mixed organic feeds are now commonly available, especially at independent garden centers. If you want a sense of just how many sources of nutrients are available from the natural world, check out Sachs's Web site at http://www.norganics.com.
But for those who want to design their own concoctions, a visit to an animal feed store and a garden center might be required.
In her nutri-mix, Harmon uses equal amounts of a variety of dry products, namely alfalfa meal, cottonseed meal, kelp meal, a chicken guano named Cockadoodle Doo, and Milorganite, made from composted human waste. She adds a little Epsom salts for the magnesium. For annuals and perennials, she adds rock phosphate to promote blooming. In the fall and winter, when roots are growing, she adds more potassium in the form of mined potash.
How do you apply this stuff? Scratch it into the root zone using a three-pronged cultivator. Harmon uses a pound per foot of height on trees and shrubs, and a pound per square foot for plantings of perennials and annuals. In containers, she blends it into the top inch or so of the potting mix and then covers the application with a thin dressing of pine fines to mask any odor.
Nick Weber, a rosarian in Brookeville, swears by a recipe passed on to him several years ago by another rose grower.
He takes a 50-pound bag of soybean meal, a 50-pound bag of alfalfa meal, 36 pounds of cottonseed meal, 20 pounds of dried blood and 15 pounds of bone meal. Those are mixed thoroughly (he uses a plywood sheet to do this; a large wheelbarrow also may serve as a mixing bowl) and stored in a 32-gallon trash can with a secure lid. The mix musn't be exposed to water, or it will break down and reek.
He takes an old coffee mug and applies two mugfuls of the blend to each rose (and other woody shrubs). He scratches it in, waters it and waits a couple of weeks before mulching, to allow the materials to break down. He feeds twice a year, once in the spring and again about eight weeks later. In addition to increasing the size and vigor of the plants, the feed results in the development of more flowering shoots.
Weber recalls having an old moribund climber named Souvenir de la Malmaison with one bud eye on it that he fed in early spring. In applying the fertilizer he knocked the bud off, normally a death blow, but "by rose time the thing was knee high and had four blooms on it."
Selected sources of granular organic ingredients: Farm and Home Service, stores in Germantown, Sykesville and Ellicott City, Md.,http://farmandhomeservice.com; Countryside Natural Products, Fisherville, Va., 888-699-7088,http://www.countrysidenatural.com; and Biocontrol Network, Brentwood, Tenn., 800-441-2847,http://www.biconet.com(mail order).