Get the most from your kitchen scraps to create compost

DEBRA M. OF SANTA ROSA ASKS: I have ?2 horses that create a lot of manure. Can you please advise me on how to best turn the manure into beautiful compost?

When large volumes of organic substances such as manure and kitchen and yard wastes are combined and slowly decompose, they reduce into a small volume of beautiful, rich, wonderful soil amendment called compost. Best of all, composted horse manure is a valued source of slow-release soil nutrients beneficial to your pasture or garden, and a compost pile can recycle organic wastes from your home, turning kitchen scraps, plant material and small wood products into a dark, sweet-smelling garden amendment/fertilizer that will provide your plants nutrients such as nitrogen, phosphorus, potassium and secondary trace elements.

Using compost is a good way to improve problem areas in your soil such as drainage, aeration and the ability to retain nutrients and water, in both sandy and clay soils.

As you build your compost pile, alternate between dried brown material, which provides carbon, and moist green material, which provides nitrogen. Both materials are necessary to start the decomposition process.

Browns (carbon) may be cardboard, dry leaves, uneaten hay, dried plant clippings, straw, shavings, newspaper and small pieces of bark. Greens (nitrogen) include grass and fresh plant clippings, fruit and vegetable food scraps and manures from chickens, cows, horses, pigs, poultry and rabbits. Do not add dog or cat manure and avoid fats, meats and bones.

To give the hardworking microorganisms a hand at decomposing your pile, break large pieces into smaller ones. If your compost pile doesn’t have enough nitrogen, it won’t heat up and decompose. If the nitrogen proportion is too high, the compost may become too hot, killing the composting microorganisms, or go anaerobic, resulting in a foul-smelling mess.

Guidelines: The composting process can be a little tricky, but it’s not rocket science. The simplest method, especially when you have a large volume of manure, is to build the compost pile and let it sit for six months to a year, after which the compost will be ready. If you have a small amount of manure generated each day from your horse or horses, you can create compost in a few months. Here’s how:

1. Choose the right location: A level, well-draining spot that is easily accessible year-round is best.

2. To bin or pile? This depends on how many compost piles you want, how big you want them to be and if you have access to a tractor. Contain the compostable materials in a heap, usually dome-shaped, or in a three-sided bin that can be made of wooden pallets standing on edge. For the decomposition process to work, the pile should be no smaller than 3 feet by 3 feet by ?3 feet. The bin system helps keep the pile contained, neater and easier to manage. Bins can also be made using straw bales, lumber or cinder blocks.

3. Create the pile by alternating layers of green and brown materials. The green layers should be about 4 inches thick and the brown layers about ?8 to 10 inches thick. Start with the brown material as the base. Water down each layer after it is added, making sure the dry material is slightly moistened. Don’t just give it a light sprinkle.

4. To cover or not to cover? Covering the compost pile with a tarp or a roof during the rainy season will help prevent valuable nutrients from washing away and the pile from becoming a soggy mess. If you have open space nearby covered with weeds, cover the compost pile to prevent weed seeds from blowing onto the compost.

5. Aerating the pile: Oxygen is an important component to composting because the bacteria and fungi that break down the organic matter require oxygen to do their job. If your pile is big enough, use a small tractor to turn the pile. If not, turn it by hand using a pitchfork. If there’s not enough air in the pile, it will have a foul smell rather than a nice earthy smell. How often you turn it will determine how quickly your compost will be ready to use. Mix the layers every so often, say, once every two weeks. The longer the interval between mixing, the longer it will take for the compost to be ready.

6. Keep it damp: The compost pile should be like a wrung-out sponge, damp, but not dripping wet.

7. Monitor it: The beneficial microbes breaking down the material cause the pile to become fairly warm, about 110 to ?160 degrees Fahrenheit. You want this to happen. Parasites and pathogens begin to die when the compost reaches at least 130 degrees for at least three days. You can monitor temperatures easily using a long-stemmed compost thermometer purchased at a plant nursery or garden store.

8. The end result: After a few months, depending on how frequently you turned the pile, you will see the materials looking like compost material. Worms and small insects will move in and break it down even further, creating the finished product. You will know your compost is ready when the material looks evenly textured, crumbly and dark-colored like soil and smells like earth.

Dana Lozano and Gwen Kilchherr are garden consultants. Send your gardening questions to The Garden Doctors, at pdgardendoctor@gmail.com. The Garden Doctors can answer questions only through their column, which appears twice a month in the newspaper and online at pressdemocrat.com.