A friend of mine had a bad case of indigestion last summer, but not in his tummy. It was in his compost pile. "Nothing's breaking down," he said, eager to have plenty of black gold to spread on his garden in the fall. "It just sits there. What am I going to do?"

Sooner or later the organic materials my friend had assembled in his pile would have decomposed, as organic matter always does. The bumper sticker that reads "Compost happens" tells a true tale. But there are ways to make it happen more in line with a gardener's urgent schedule. For best results, you need an equal mix of carbon-rich and nitrogen-rich ingredients. Carbonaceous ones tend to be dry, brown stuff such as dead stems, straw, sawdust or dead leaves you've chopped up with your mower. Nitrogenous ones are moist and usually green, such as weeds, grass clippings, spent crops, manure and kitchen waste. For a heap to properly cook (that is, to heat up as it is being digested by bacteria), brown and green must be placed in commingling layers.

Think of the brown as the fuel and the green as the fire that ignites it. If you've just added a lot of tough dead flower stalks, which break down slowly, pile on green matter at the same time for balance, or vice versa. A heap without enough carbonaceous materials will fire up too quickly, then sit and turn anaerobic and smelly.

Make sure enough air enters the heap. One old trick is to start with a layer of shrub or tree prunings on the bottom to create air channels, then set an upright bunch of them in the center as a chimney. Moisture is also essential, so you'll need to add water in dry weather.

If an established heap is sluggish, try turning it, bringing the outer portion to the center. As you go, break up compacted layers and sprinkle water as needed, along with a guaranteed fire-starter, such as seaweed, fish emulsion or the chopped-up remains of a lobster dinner – but no meat scraps. Molasses, diluted to half a cup per gallon of water, is a soluble carbon source that stimulates bacterial activity and is high in potassium and trace minerals. Some people add skim milk or coffee grounds discarded by local coffee shops.

Don't forget the simple power of fertile earth. The soil that clings to the weeds you add to your pile is full of microorganisms, worms and other allies, all set to multiply and join the party. If weeds aren't available yet, a few shovelfuls of your most fertile soil will inoculate the pile with life. Just what the doctor ordered.

Barbara Damrosch will demonstrate gardening in large containers at Smith & Hawken's Dallas location (3300 Knox St.) from noon to 2 p.m. April 18. Her all-new, 20th-anniversary edition of The Garden Primer (Workman Publishing, $18.95), an organic resource, will be available.