by Jan Phipps, Edgar County Master Gardener
More and more gardeners are becoming interested in organic-based soil fertility. The basics start with the pros and cons between compost, composted manure, and organic-based fertilizers, according to Christopher Enroth, Illinois Extension horticulture educator. To start, organic refers to materials from living or once-living organisms or their waste. Conversely, synthetic fertilizer derives from inorganic chemistry.
COMPOST is a soil amendment that adds protein, beneficial bacteria, and fungi to soil aiding the micro- and macro-organisms in healthy soil. Yard waste (decomposed leaves, grass clippings, etc.) and vegetative food scraps comprise most composts. Vermicomposting produces castings from worms.
The benefits of compost include recycling waste products, a guarantee it won’t burn your plants, and the knowledge it is building the soil structure in your gardens. The drawbacks are compost is expensive if purchased instead of making your own. It doesn’t offer a lot of plant nutrients compared to fertilizer, so it is not enough for vegetable gardens which are high-demand crops. Any chunks not broken down adequately will tie up the nitrogen in the soil, making it unavailable for plant use. A way to mitigate this problem is laying the not fully composted material on top of the soil instead of mixing it in.
COMPOSTED MANURE comes from animal waste, and it should be fully composted and not used fresh because it carries pathogens harmful to humans. E. coli can live in uncomposted manure for 21 months. Composted manure has many of the same benefits as compost; plus, it adds protein and organic matter to the soil and uses a product otherwise viewed as waste. Composted manures are cheaper than commercial compost, and if you have herbivore pets or livestock, you can compost your own for free.
The downside is manure must be fully composted since it can harbor harmful pathogens. The nutrient levels also differ wildly depending on the species of animal which produced the waste resulting in soil fertility that is no longer balanced if over-applied. Composted manure is often full of water and therefore heavy to handle. Manure from grazing animals contains weed seeds, many of which will survive the composting process.
ORGANIC-BASED FERTILIZERS derive from manufacturing processes that produce by-products. Bone meal, blood meal, alfalfa meal, corn gluten meal, milorganite, and fish emulsion are the main ones and come in products that are applied like traditional fertilizers.
The advantages of organic-based fertilizers are using a manufacturing by-product in a way that improves your soil, adds protein for the beneficial organisms and provides nutrients to your plants. It is a good choice when preparing landscape and garden beds because of its slow-release, long-term properties. Those same properties can be considered a disadvantage for homeowners looking for instant results. Also, there is an erroneous perception that organic-based fertilizer will not burn plants like synthetic fertilizer if over-applied. Some can, so always read and follow the directions on the package.
Call the Illinois Extension Master Gardeners of Edgar County with your gardening questions at 217-465-8585.
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