The Quick and Easy Guide to Homemade Organic Fertilizer

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

  • homemade organic fertilizer - author in thriving garden
    Steve Solomon’s garden soil and crops show the effects of steady applications of his homemade organic fertilizer. Solomon has written nine books on gardening and maintains an online gardening resource.
    Photo by Muriel Brown (Chen)
  • homemade organic fertilizer - bags of mix ingredients
    Organic fertilizer ingredients are less expensive when bought in bulk. The basic organic fertilizer ingredients are seed meal, agricultural lime, gypsum, dolomitic lime (or dolomite), kelp meal and bone meal, rock phosphate or high-phosphate guano.
    Cheryl Long

  • homemade organic fertilizer - author in thriving garden
  • homemade organic fertilizer - bags of mix ingredients

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.

7/11/2021 8:54:11 PM

Thank you for your commitment to organic gardening and for developing the Complete Organic Fertilizer. Is the COF recommended for plants such as perennial, annuals, shrubs, trees, and houseplants? If it is at what rates? If it is not, what are some sources for recipes for organic fertilizers for these plants? Thanks again.

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