Right shredder is a boon for making good mulch

Sometime around the turn of the century, a Canadian by the name of Nelson Kemp saw the need in the garden-and-nursery industry of a machine that would pulverize manures, rock phosphate, compost, and soil.

Pulverized organic materials can be spread on gardens so much more easily and look a whole lot more attractive, he reasoned.

Kemp was working for his father in a manufacturing business specializing in horticultural and agricultural machinery, and pretty soon he had added to the company's product line. What he came out with was the first-ever garden shredder, a hammermill-type machine that did what it was supposed to do and then some.

Along with the soil, phosphate, and manures, it would process many other materials. It could take sod, for instance, and in a matter of moments transform it into soft potting soild; it would turn cornstalks and sunflower stems into a relatively fine mulch. It did the same thing to vines, leaves, weeds, and brush trimmings.

These shredded materials could be used directly as a mulch or piled into a heap, where they broke down much more rapidly into compost than unshredded materials.

Indeed, quite indigestible materials became acceptable compost ingredients after passing through the shredder. Since then several generations of shredder users have helped refine the design and, all in all, gardeners have had cause to be grateful to Nelson Kemp ever since.

Today, there are many manufacturers of garden shredders, although the number is down from the more than a score or so companies of a decade ago. Apparently, demand for the machines continues steady for those companies that are still in the business.

While a majority of shredder owners appreciate their machines and make good use of them, a few people find them disappointing. In most cases, however, they haven't bought the shredder that fits their need.

Power shredders for the home gardener range all the way from a just-introduced electrified version of the Rotocrop hand shredder to the 8-hp. Kemp, capable of shredding 14 cubic yards of material in an hour, and similar machines put out by W-W Grinder Corporation and Amerind-MacKissic, among others.

If you simply want to process the leaves that accumulate in your yard each fall, plus a little garden waste, then many of the smaller models will perform very adequately for you, including those that operate on the rotary-mower principle, by which two or three cutting blades rotate on a horizontal plane, often passing between additional stationary blades.

But, while these rotary-blade machines grind dry materials very fine, they become hopelessly gummed up when wet materials, including succulent garden waste , are introduced.

If composting is a major part of your garden program you will need a hammermill-type machine that literally bludgeons everything into small pieces -- from hard soil clods, including accidentally inserted small stones, to inch-diameter tree branches. The size of your yard and the volumes of compost you produce will govern the size of your machine. Even hammermills can be gummed up by wet materials (dry, brittle materials always shred best), but most models have ways of getting around these problems.

Some machines have a series of bars through which the shredded material must pass. By removing some of these bars and creating wider openings, wet materials can be forced out.

Machines with screens, resulting in finer shredded materials, have no such facility, but generally compensate by having an adjustable opening that allows the wet material to bypass the screen.

This results in a more coarsely ground material, but even partly ground green wast decomposes so much faster than unground material that this is perfectly acceptable. If you want a finer grind, simply pass the material through the shredder two or three times.

Shredders do not come cheap, with $200 to $900 the current price range. Thus , the question remains: Is the expense justified?

I didn't think so at first. But I wanted a shredder just the same, so I justified it by looking on the shredder as my set of golf clubs. tently used tool in my garden, I have come to see it as a worthwhile tool in itself. What it has saved me in the purchase of fertilizer and mulches over the years has repaid the initial cost several times over.

If you are thinking about buying a shredder, be sure you shop around first. Below is a partial list of shredder manufacturers. When writing to them ask a few questions: What materials will the machine shred? How does the shredder handle wet materials, if at all? What is its capacity in cubic yards per hour? What size materials will it process (thickness of tree branches)?

The answers to these questions should tell you which machine will best meet your particular needs. Ask, too if the machine comes with an electric motor option. A gasoline engine means that your machine can be trundled to wherever you have materials to shred. In a small garden, however, the electric motor has distinct advantages. It is largely maintainance free, has a long life expectancy if it is not abused, is much quieter than the gasoline engine, and has the convenience of being turned on at the flick of a switch.

Be warned, however, that shredders are dangerous machines. Observe all safety recommendations. Part of the high price of today's shredder results from the somewhat careless use of a machine a few years ago. The resulting lawsuit saw shredder manufacturers' insurance rates skyrocket.

Here is a partial list of manufacturers:

Amerind-MacKissic, Box 111, Parker Ford, Pa. 19457; (215) 495-7181.

Kemp Shredder Company, 3175 Oregon Pike, Leola, Pa. 17540; (717) 656-2991.

Lindig Manufacturing Corporation, Box 111, St. Paul, Minn. 55113; (612) 633- 3072.

Rotocrop, 604 Aero Park, Doylestown, Pa. 18901; (800) 523-2580.

Roto-Hoe Sprayer Company, 100 Auburn Road, Route 87, Newbury, Ohio 44065; ( 216) 564-2294.

Toro Company, 8111 Lyndale Avenue, South, Bloomington, Minn. 55420; (612) 883 -8801.

W-W Grinder Corporation, Box 4029, Wichita, Kan. 67204; (316) 838-4229.