Natural Soil Amendments for Your Garden

Natural soil amendments like greensand, colloidal phosphate and kelp meal may sound like the stuff of alchemy, but they can work wonders in a garden.

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    Once you know your natural amendments and your garden's needs, you can mix up a batch of fertilizer that's "personalized" for your plot.

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Greensand? Colloidal phosphate? Kelp meal? Natural soil amendments may sound like the stuff of alchemy, but they can work wonders in your garden. 

Natural Soil Amendments for Your Garden

TRUE, SHAKESPEARE'S WITCHES weren't brewing fertilizer when they chanted their famous incantation in Macbeth But surely the ingredients of the organic soil boosting trade sound almost as strange as the "eye of newt and toe of frog" the Bard's spellcasters did use.

Furthermore, the proper use of natural soil amendments can seem pretty mysterious. Most gardeners are familiar with compost, but each time a neighbor sees my husband, Franklin, and me with a sack of greensand or hoof and horn meal in tow, we have to explain what that powder is and what it's for. Natural soil amendments are used for correcting specific major or minor nutrient deficiencies in your plot. They are not replacements for compost (which adds and feeds microbial life, increases nutrient availability and improves soil texture, balance and drainage—as well as adding nutrients).

In fact, a good composting and cover-cropping program, which recycles all unused plant material, can probably—unaided—maintain the fertility of an established, productive organic garden. But unless you've been gardening in one location for a long time with consistently good results, chances are your soil could use a little nutritional shot in the arm. Maybe you're using a new spot that's currently low on compost or in transition to organic methods. Perhaps your soil has a minor, long-term deficiency you've never addressed. In such instances, proper use of natural amendments can boost growing success.

But how can you tell for sure if you need soil amendments? How much fertilizer constitutes "proper use"? How often should you use them? To get the answers to these and other questions, I consulted several gardening experts: Steve Rioch of Timberleaf Farm (he runs a soil-testing service and does related research); John Jeavons (the director of Ecology Action, a research center for bio-intensive techniques, and author of the classic guide How To Grow More Vegetables ); Robert Parness (of Woods End Laboratory and author of the very thorough text Organic and Inorganic Fertilizers ); and White Eagle "Otto" Wylie (a former soil tester who now manages an organic farm and biodome).

And what enlightening conclusions did I come away with after tapping these soil-centered minds? First, I found out rather quickly that you can ask such experts all the simple questions you want, but you'll never (and I mean never) get simple answers. In fact, I spent so much time on the phone listening to in-depth explanations that the phone company sent me a nice letter suggesting that I check to see if someone else wasn't using my line and running up my bill! The discovery that soil fertility is a complex subject did convince me of one thing: A soil testing service that specializes in making recommendations to organic growers is the way to go. All my experts agreed wholeheartedly.

"If a person is looking for a `one size fits all' prescription for a garden but doesn't want to bother with a good soil test, the only thing my conscience would let me recommend is adding compost," says Steve Rioch. Remember, though, that nutrient-poor soil produces nutrient-poor compost, and if you try to enrich a plot with materials grown on that plot, you'll still end up with the same deficiencies. The moral, then, is if you want to know how to best improve your soil's fertility, get a good soil test. My experts suggest using organically minded soil testers. If, instead, you get a state extension test or use a home-testing kit, the recommendations will be for specific doses of chemical fertilizers.

Les Tollefson
4/18/2007 7:28:42 PM

I would like to find a source for hoof & horn meal. Can you help ?



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