Clueless about compost? Expert shares timely tips

CORVALLIS, Ore. – As leaves fall and yard debris bins fill up, it’s a good time to think of a different solution to having all those resources trucked away.

“Compost is good for the environment and for the garden,” said Ross Penhallegon, horticulturist with Oregon State University’s Extension Service. “You take all these things you don’t know what to do with – grass clippings, leaves, garden refuse, anything left over – and throw it into the compost pile. Then it decomposes and you put it back into the soil. It’s a sustainable system.

“Plus, compost provides inexpensive, nutrient-rich material,” he added. “It’s one of the best soil builders there is.”

For beginners, Penhallegon teaches the easy “one-third” system of composting. Layer a third manure or carbon material, a third nitrogen material and a third soil. The carbon ingredient, known casually as brown stuff, includes dried leaves, woody plant prunings, straw and sawdust. The nitrogen part, or green stuff, is composed of grass clippings, soft prunings and animal manure.

Other things such as coffee grounds, tea leaves, egg shells and kitchen scraps can be thrown in as well, but Penhallegon warns they can attract unwanted guests like rats, opossums and raccoons. Don’t add pet waste, meat, dairy products, fats or diseased or poisonous plants.

Getting the right amount of air and water into the pile is key, he noted. You don’t want too much water or the microbes and other critters that break down the material can’t do their job. On the other hand, a too-dry situation stops the process, too. The idea is to keep the pile moist, but not soggy, especially during the winter months. Too little air can also bring decomposition to a halt. The more you turn the pile, the more air gets introduced, keeping everything on track.

Of course, everything decomposes given time, but following a few steps makes it happen a whole lot faster.

Penhallegon’s tips for making compost:

  • Locate the compost pile on well-drained soil in sun or shade. Place on plastic to prevent unwanted insects from moving into the compost pile.
  • You can build containers out of materials such as wood pallets, concrete blocks or chicken wire, but a large pile works just as well.
  • Start pile with a layer of twigs or small branches to enhance air circulation and drainage.
  • Add material – carbon, nitrogen and soil -- in three layers of about 2 inches. You can repeat the layers, but don’t make it much taller than 3 feet.
  • Sprinkle the pile with water. Check moisture periodically by squeezing a handful of compost ingredients. It should feel like a wrung-out sponge. If it’s too wet, add some dry material and turn to mix.
  • To retain heat and keep rain from saturating pile, cover it if possible with a piece of plywood, plastic, tarp or burlap sacks.
  • Turn the pile once a week to keep air circulating. Re-cover the pile after each turning.
  • Check pile periodically to monitor the amount of heat being generated. If it’s heating up, the right balance of ingredients has been added. If it isn’t, add green material and turn the pile to mix and aerate. Water if necessary.
  • After two to three months, the pile should no longer heat up and will smell and look like fresh, crumbly soil. The original material shouldn’t be readily recognizable; though small pieces may still be evident.

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