Using manure as a soil additive for gardens

Published on November 1, 2009

by Jo Ellen Meyers Sharp

Most of us know about compost as a soil amendment, but mention manure to a lot of people and they, well, hold their noses.

When I suggest manure as a soil additive, you can see the resistance in people. "Doesn't it smell?" they ask. No — it has a rich, earthy fragrance and cow manure comes in 40-pound bags, which is convenient when you think about the alternative of scooping it up yourself.

Animal manures are sustainable, plentiful and do a terrific job of improving the soil. They work slowly, releasing trace elements of nitrogen and other soil-building microorganisms. Over time, these organisms make the soil loamy and organically rich with improved drainage and moisture retention.

Dig manure into the soil when making new beds and add it to the vegetable garden after fall cleanup. Work it in the soil around existing perennials, shrubs and trees. Manure also can be added to the compost pile as a way to get it cooking. Here's the poop:

Most fresh or raw manures are not recommended for plants because it's "hot," containing urine, enzymes and other matter that will burn plants, or they may have disease-causing bacteria.

If you have fresh manure, it can be applied in fall to new, unplanted beds. Work it in the soil or layer it a few inches deep on the soil surface. It will break down over winter and the bed will be ready for planting in spring. Always use care when handling fresh manure. Wear gloves and thoroughly wash your hands and clothing after use.

Rotted, aged or composted manures are recommended for most gardeners. They won't burn plants because they've gone through a natural or manufactured process that reduces or eliminates weed seeds and disease-causing agents.

Green manure is a soil-building crop, usually legumes or annual grasses, sown in fall for winter cover, then turned into the soil in spring before planting. Green manures add nitrogen to the soil or help hold it there for the plants to use, along with other micronutrients.

And, uh, who makes the best?

Cow — Considered one of the best because what a cow consumes goes through its four stomachs, which reduces or eliminates weed seeds. Usually available in bags at garden centers.

Horse — Also considered a good choice and is usually readily available at stables, where it's frequently mixed with straw, newspaper or other organic matter, which is an added bonus. Horse manure can be hot and contain a lot of weed seeds, so it's best to allow it to age, rot or compost before use.

Pig — Should be composted before use because it's hot and may contain disease organisms. Not usually recommended for gardens.

Poultry — Should be composted before use because it's hot and has a bad odor.

Rabbit — Can be used fresh, mixed in the soil. Is generally high in phosphorus, which is the nutrient used for good flower and fruit production.

Sheep — Should be composted before use because it's hot.

Manures from dogs, cats and other carnivorous animals aren't recommended because they may harbor disease pathogens, which are contagious to humans. Many of these pathogens may survive the composting process.

Sometimes known as the Hoosier Gardener, Jo Ellen Meyers Sharp lives in Indianapolis and is part owner and editor of Indiana Living Green magazine. Her work has also appeared in many other publications, including The American Gardener, Garden Gate and Greenhouse Grower. In addition, Meyers Sharp speaks about gardening and sustainable living throughout the Midwest and is a director of the Garden Writers Association.