The Quick and Easy Guide to Homemade Organic Fertilizer

Find out how to mix up a proven homemade organic fertilizer recipe.

| June/July 2006

Three decades of experimentation have led me to the following recipe for homemade organic fertilizer. I call it Complete Organic Fertilizer or COF. It should work well in most parts of the U.S., although factors such as clay-to-sand ratio of magnesium-to-calcium ratio can affect results. See my companion piece A Better Garden Fertilizer for a discussion of that and soil testing.

Organic Fertilizer Recipe  

Measure all materials by volume — by the scoop, bucketful, jarful, or whatever container you want to use, as long as it's the same for each ingredient. Proportions can vary 10 percent either way and still produce the desired results. Mix uniformly:

4 parts seed meal
1/3 part ordinary agricultural lime, best finely ground
1/3 part gypsum (or double the agricultural lime)
1/3 part dolomitic lime

Plus, for best results:
1 part bone meal, rock phosphate or high-phosphate guano
1/2 to 1 part kelp meal (or 1 part basalt dust) 
1/2 level kitchen measuring teaspoonful (carefully measured) of ordinary washing borax per each four quarts of seed meal.**

**Overdoses of boron can poison soil. The acceptable range for boron is not very wide. Too little and you get hollow hearts and brown centers on brassicas and potatoes. Too much and everything is stunted or dies. Measure carefully! Blend this material carefully and thoroughly into your COF before spreading it. If this precision seems daunting just don't bother.  

How Much to Use

Once a year (usually in spring), before planting crops, spread and dig in the following materials.

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