Organic matter does so many wonderful things for a garden, it’s just silly not to take advantage of it. There would be no organic gardening without organic matter. Decaying organic matter is how plants are fed in nature. Unfortunately we’ve become very tidy landscapers and we tend to remove any dead plant material that falls onto our lawns. It would be so much more beneficial to allow the fallen leaves to blow off into the bushes, where they will not only feed the soil, they also prevent erosion and mulch the soil.
Organic matter added to garden soil improves the soil structure and feeds the microorganisms and insects. The more beneficial microorganisms your soil can support, the less bad organisms will survive. The good guys feed on harmful microbes like nematodes and certain soil born diseases. They also release their nutrients into the soil when they die. So the more beneficial microorganisms that are in the soil, the more nutrients will be in the soil. And many types of organic matter add still more soil nutrients to the mix.
Organic matter also contains acids that can make plant roots more permeable, improving their uptake of water and nutrients, and can dissolve minerals within the soil, leaving them available for plant roots.
Types of Organic Matter
- Compost is the poster child of organic matter. Compost is any kind of decayed organic matter. You can make your own or buy it by the bag or truckload. Finished compost looks like rich soil. It’s dark and crumbly with an earthy smell. By the time the compost cooking process is complete, weed seeds, fungus spores and other undesirable elements that may have gone into your compost bin, should no longer be viable. Compost can be added to your gardens at anytime, either turned into the soil or used as a mulch or top dressing.
While it is advised that you keep perennial weeds, pesticide treated material and diseased plants out of your compost bin, most every other form of plant material is fair game.
- Grass clippings
- Garden Waster (from weeding, deadheading, pruning...)
- Vegetable Peels
- Manure Aged animal manure is an organic material with an added bonus of soil nutrients. Animal manure must be aged for 6 months to a year, before it is applied to the garden. Fresh manure will burn your plants, may contain bacteria that can cause illness from contact and it stinks. You can add fresh manure to a compost heap and let it age there.
Cow, sheep and chicken manure are the most popular varieties, but there are several more. The manures to avoid because of their disease potential for humans are: cat, dog, pig and human manures.
- Green Manure Green manures are basically cover crops that are grown with the intention of turning them back into the soil. Obviously this would be more useful in the vegetable garden or in a newly created bed where tilling will not harm existing perennial plants.
Different green manures offer different advantages. Some, like alfalfa, are grown for their deep roots and are used to breakup and loosen compacted soil. The legumes, clover and vetch, have the ability to grab nitrogen from the air and eventually release it into the soil through their roots. If allowed to flower, clover especially is attractive to pollinators and beneficial insects. All green manures will suppress weeds and prevent erosion and nutrient runoff in areas that would otherwise be unplanted. And they all assist with creating good soil structure and food for the microbes, once they are tilled in and begin to decompose.
Popular choices for green manure include: annual ryegrass. barley, buckwheat, clover, winter wheat and winter rye.
The nutrients in your soil are the final component in building healthy soil. Just like people, plants need certain nutrients to grow and to fend off disease. Organic fertilizers can be made from plant, animal or mineral sources and are basically returning what was taken from the soil. Organic fertilizers are released slowly, which means that plants can feed as they need to. There is no sudden change in the makeup of the soil which might harm the microbial activity.
Building healthy soil is an ongoing process. By making healthy soil a focus at the start of making a garden, you will have a head start on creating a sustainable organic garden.
Read more about gardening with nature in Organic Gardening Essentials.