Mother Earth Gardener

Organic Fertilizer Options

Photo by Getty Images/MarioGuti.


What are some recommended organic fertilizers that I can use for my garden?


Organic fertilizers, whether they’re meals, manures, or composted plant material, contain N-P-K (nitrogen-phosphorus-potassium), trace minerals, enzymes, vitamins, and lots of organic matter. Of those ingredients, 100 percent are useful to the soil and plants. In contrast, synthetic fertilizers contain no organic matter. Soil microorganisms must have this carbon energy source, and, if it isn’t provided, the microbes will take it from the soil. That drains soil health with every fertilizer application.

The most important material in an organic garden is organic matter that becomes humus during the decomposition process. Humus becomes humic acid, other benefi cial acids, and mineral nutrients. Organic fertilizers are better than artificial products, because they’re the derivatives of plants and animals and therefore contain most or all the trace elements that exist in growing plants and animals. In addition, organic fertilizers are naturally slow-releasing and provide nutrients to plants when they need it. Synthetic fertilizers glut the plants with nutrients immediately after application, which is usually at the wrong time.

Here are some of my recommendations for natural, organic fertilizers to boost your garden’s production and build soil health:

Alfalfa meal.

This fertilizer provides many nutritional benefits for plant use and soil organisms. One very important ingredient is triacontanol, a powerful plant-growth regulator. Alfalfa is very high in vitamins, plus N-P-K, calcium, magnesium, and other valuable minerals; sugars and starches; proteins; and fiber. Use at 10 to 20 pounds per 1,000 square feet.

Coffee grounds.

Apply old coffee or grounds directly to the soil in beds or potted plants.

Both are acidic and loaded with nutrients, including N-P-K.


This is the best organic fertilizer and is key to any organic gardening program.

It’s high in nutrients, humus, humic acid, and microorganisms (analysis will vary based on ingredients). The best composts are made from a variety of local organic materials, such as hay, sawdust, manure, leaves, twigs, bark, wood chips, dead plants, food scraps, pecan hulls, and grass clippings.

Earthworm castings.

These are high in bacteria, calcium, iron, magnesium, sulfur, and N-P-K, and have more than 60 trace minerals. They’re an excellent ingredient in potting soil, in flats when germinating seeds, and to toss into planting holes. They’re gentle, sweet-smelling, and clean.


Rabbit, llama (sometimes called “llama beans”), and alpaca manures can be applied directly without fear of burning plants. Because of their high nitrogen content, cow, horse, sheep, turkey, and chicken manures should be composted prior to use. When composting, mix manure with leaves, sawdust, straw, and other vegetative material. Use chicken litter from your own birds or from a grower you trust, because commercial chickens may be fed ingredients you don’t want in an organic garden.


This is a basic mineral often lacking in alkaline soils. Apply granulated sulfur at 5 pounds per 1,000 square feet twice annually to help lower base saturation of calcium and raise magnesium. Be careful not to breathe dust, over-apply, or use when planting seed. Sulfur can act as a pre-emergent. It shouldn’t be used in acidic soils.

—Howard Garrett, host of “The Dirt Doctor” radio show and author of more than a dozen books, including The Organic Manual.

  • Published on Feb 26, 2019
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