BULID BETTER GARDEN SOIL WITH ORGANIC FERTILIZERS.

As more and more people recognize the many benefits of organic gardening methods, a fresh crop of organic fertilizers are sprouting on store shelves. Many are overpriced, and some are stunning rip-offs that reputable stores and catalogs should be ashamed to sell. The really amazing thing is that two of the best organic fertilizers are easily available to most of us absolutely free!  It’s definitely a buyer-beware world out there. If you’re not careful, you could pay five, 10 or 4,000 times more than necessary to get the nitrogen and other nutrients you need. Here's what we found when we evaluated the pricing for 21 fertilizers:

The Best Free Fertilizers

All products labeled as “fertilizer” must be labeled with their content of the three major plant nutrients — nitrogen, phosphorous and potassium (N-P-K). Most organic fertilizers are bulkier than synthetic chemical products, so their N-P-K percentages are typically lower than synthetic products, and their application rates are higher.

Also, because organic products are biologically active, their N-P-K numbers may change somewhat from batch to batch and over time. Because of this, it can be hard for producers to comply with the labeling laws. As a result, some excellent organic fertilizer options, such as compost, often are not even labeled as a “fertilizer.” One of the best free fertilizers, grass clippings, break down so quickly that they can’t be bagged and sold.

But make no mistake, compost and grass clippings do what fertilizers are supposed to do: They enrich the garden soil with nutrients that plants and microscopic soil life-forms are eager to use. In most areas, you can easily collect grass clippings from your neighborhood, bagged and set out ready to bring home. And many communities make yardwaste compost (made mainly from grass clippings and leaves) available for free.

So, if you can get free clippings or compost, how much should you use? Here are guidelines prepared with help from soil scientists at Woods End Laboratory in Maine.

Grass Clippings: Just Half an Inch Will Do!

Grass clippings are one of the best organic fertilizers. Not only because it’s easy to find free local sources, but also because the clippings do double duty preventing weeds and conserving garden soil moisture when used as mulch — two things other fertilizers cannot do. Nitrogen content of clippings will vary, with fresh grass collected in spring from fertilized lawns topping 5 percent nitrogen, while clippings from later in the year or from unfertilized lawns will likely contain around 2 percent nitrogen. (Be sure to avoid clippings from those “perfect” lawns that have been treated with herbicides.) BY CHERYL LONG AND BARBARA PLEASANT.