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Add natural fertilizers to make compost piles richer

"Will I need additional fertilizers even with compost?" a column reader asks.

Possibly. The answer depends on the amount of compost processed annually and how well a mulch program feeds an increasing earthworm supply. To be on the safe side, natural fertilizers can be added.

Plants require a number of minerals to achieve adequate growth. I heap on the compost and add other natural fertilizing ingredients from time to time, but even in the face of plenty, plants seldom overindulge.

Well-known packaged natural fertilizers include dried cow manure, dehydrated sheep droppings and dolometic lime, usually available in garden centers. Others, sometimes advertised in natural gardening magazines, must be ordered by mail.

Some natural gardeners favor rock fertilizers. Four commonly used include dolomite, granite dust, basalt and phosphate.

Dolomite, processed from rock, is perhaps the best known. It contains varying amounts of magnesium, a vital growth element.

Granite dust, a source of potash, contains trace minerals needed during plant production. It may be applied as a top dressing at the rate of 1 pound to 10 square feet of soil.

Basalt rock, found especially in New England coastal areas, provides potassium, magnesium, calcium and iron. It can be applied either directly to the soil or spread on composting materials.

Phosphate, a rich source of phosphorus and trace minerals, is quarried, principally in Florida. Processed to a readily usable consistency, it can be applied to a garden plot by a mechanical spreader or by hand.

In some areas, natural fertilizers are available for the hauling.

If you don't have a pickup or a utility trailer, an automobile trunk will do. I use a substantial plastic tarpaulin, large enough to protect the car's trunk, when getting seaweed, leaves, barnyard manures and poultry litter. A quick hosing and drying of the plastic prepares it for future pickups.

A nearby riding stable, eager to dispose of its horse stall accumulations, offers the product without charge.

Seaweed, high in potash and trace minerals, makes a prime addition to any compost pile. It also provides desirable mulch for garden plants.

Animal sections of fairs and zoos sometimes offer manures for the hauling. Usually it's fresh and requires closed plastic bags during transport. To avoid offensive odors, cover with soil immediately.

Fellow gardeners and garden clubs may reveal other free natural fertilizer sources.

Leo Van Meer's book, Natural Gardening, is available from Van Meer Publishing, P.O. Box 8127, Clearwater, FL 34618 ($10.95 post-paid, plus 77 cents sales tax). Address questions to Garden Naturally, the Times, P.O. Box 1121, St. Petersburg, FL 33731.