A Better Way to Fertilize Your Garden: Homemade Organic Fertilizer

Image Gallery 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: MURIEL BROWN (CHEN)

Because my garden supplies about half of my family's yearly food intake, I do all I can to maximize my vegetables' nutritional quality. Based on considerable research and more than 30 years of vegetable growing, I have formulated a homemade fertilizing mix that works great in most food gardens. I call it Complete Organic Fertilizer, or COF. It is a potent, correctly balanced mixture composed entirely of natural substances. It's less expensive than similar commercially compounded organic fertilizers, and it's much better for your soil life than harsh synthetic chemical mixes (see "Chemical Cautions" below).
The use of COF plus regular, minimal additions of compost has a long track record of producing incredible results. I've recommended this system in all the gardening books I've written over the past 20 years. Many of my readers have written back, saying things like, "My garden has never grown so well; the plants have never been so large and healthy; the food never tasted so good."

Complete Organic Fertilizer

To concoct COF measure out all materials by volume: that is, by the scoop, bucketful, jarful, etc. Proportions that vary by 10 percent either way will be close enough to produce the desired results. Making this formula by weight is more difficult and I suggest you do not try to. I blend my COF in a 20-quart plastic bucket, using an old one quart saucepan as a measuring scoop. I make 7 to 14 quarts of COF at a time.

At any cost of materials this mix is a good value when judged by the results it produces, but COF can be unnecessarily expensive unless you buy the ingredients in 50 pound sacks (20 kg) from appropriate vendors. Urban gardeners may have to do a bit of research to find rural suppliers. Farm and ranch stores as well as feed and grain dealers are the best sources for seed meals and kelp meal, which are typically used to feed livestock. If I were an urban gardener, I would visit the country every year or two to stock up. The other ingredients usually can be found at garden shops, although garden centers may sell them in smaller sized packages at relatively high unit prices. You also may find the these items on the Internet but they will be less costly from farm/ranch supply stores.

Seed meals and various kinds of lime are the most important ingredients (keep reading for "Basic Organic Fertilizer Ingredients"). These alone will grow a great garden. Gypsum is the least essential type of lime, but it contains sulphur, a vital plant nutrient that is deficient in many soils. If gypsum should prove hard to find or seems too costly, don't worry too much about it — simply double the quantity of inexpensive agricultural lime. If you can afford only one bag of lime, in most circumstances your best choice would be ordinary agricultural limestone. The most fundamental nutrient ratio to get right in your soil is the balance of calcium to magnesium; it should be about 7 (calcium) to 1 (magnesium).To achieve that you could alternate agricultural lime and dolomite. First go through two bags of ordinary ag lime and then use one bag of dolomite lime. I strongly disagree with the many Rodale Press home gardening publications that insisted dolomite lime is the best single choice. Repeated use of dolomite has caused many organic gardens to become hard and compacted, making it seem that even more compost was needed than was actually required. Had the same soil had its magnesium to calcium ratio brought into proper balance, it would have loosened up by itself, seeming as though huge quantities of compost had been added.