How to Make Organic Compost

Understand what it takes for compost to be considered suitable for strict organic gardening.
Filling Your Composter

Filling Your Composter

Add organic matter to the compost pile and keep it moist so it rots. Cover the heap with old carpet to speed the process along., and avoid cooked or processed food, which attracts pests.

Photo by: DK - Simple Steps to Success: Herbs © 2009 Dorling Kindersley Limited

DK - Simple Steps to Success: Herbs, 2009 Dorling Kindersley Limited

Composting is an important part of organic gardening. Depending on the methods used, compost can be a suitable alternative to synthetic chemical fertilizers and other soil amendments. While chemical fertilizers provide a quick boost to spurt plant growth, they tend to be low in micronutrients, minerals and beneficial organisms that plants need for long-term growth. Synthetic fertilizers can also damage soil organisms, like earthworms, upsetting the soil health and ecosystem.

Although compost is made of organic material, not all composts are technically “organic” – at least not by the strictest definition of the word. The ingredients that go into truly organic compost should be free of pesticides, herbicides, synthetic fertilizers and other non-organic compounds. Below are outlined some common culprits that compromise the organic integrity of compost.

Grass clippings are a popular ingredient in many compost recipes, but lawns might be treated with synthetic fertilizers, herbicides and pesticides. These products may dissipate during the composting process, and the general consensus is that after a few months compost grown from non-organic grass clippings should be safe for vegetable gardens. However, if you want organic compost, go for untreated grass clippings.

Garden waste, like spent annual flowers and vegetables, is a good source of green material for the compost pile. If used as an ingredient in organic compost, use annual garden waste that hasn’t been treated with synthetic fertilizers or pesticides.

Manure and animal products, like blood or bone meal, can be great sources of nutrients – especially nitrogen. Bagged manure that is certified organic can be tricky to find locally. Your best bet may be to find a local organic farm and work out an arrangement if they don’t typically sell manure. Manure from an organic farm is typically free of pesticides or medications.

Plant meals, from crops like alfalfa, canola, cotton or soy, are sometimes used in place of animal products by composters who are conscious of animal rights. Composters who live near high-production areas may use plant meals for convenience. Whatever your reason, if your goal is organic compost, your plant meals should come from crops grown without synthetic chemical inputs.

Synthetic chemical products have no place in an organic compost pile. In fact, pesticides, herbicides, fertilizers and other such products can be detrimental to the goals of traditional composting. Insecticides will harm the beneficial organisms in the pile and should be avoided. Herbicides may remain tied to the organic matter in the finished compost for some time, and will have a detrimental effect on plants grown in that product. 

Some composters may try to boost the nutrient level in their compost by adding synthetic fertilizers to the pile. If you think nutrition is an issue, follow these steps. First, incorporate your finished compost into the soil. Allow a couple of weeks to pass, then send a soil sample to your state extension agency. If your soil is lacking any nutrients, apply the recommended fertilizers to the soil – not to the compost pile.

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