Enrich garden soils with worm composting

by Dean Fosdick For
| August 6, 2010 9:00 PM

Here's a promising get-rich-quick scheme for gardeners: It's called vermiculture, or worm composting, and along with super-sizing crop yields, it cuts water bills, conditions soils and repels troublesome insects.

"Vermiculture is a step up from working with the standard compost pile," said Dorothy Benoy, who with her husband, Al, owns the Happy D Ranch Worm Farm at Visalia, Calif. "It takes a bit more management, but the returns are greater."

Earthworms spend most of their time reproducing, eating and excreting, which is where their "vermicastings," or manure, comes in. Set them up for housekeeping in homemade tubs or specially made bins and you have the structure for a "wormery," where the creatures will turn table scraps into a highly enriched organic soil amendment while expanding their population many times over.

Worm castings contain five times the available nitrogen, seven times as much potash and one-and-a-half times more calcium than typical topsoil.

You can buy the product commercially (a little more than $1 per pound for castings and $15 per gallon for worm tea, plus shipping) or do it yourself. All you need is a well-ventilated container and some moistened bedding - usually shredded newspaper, computer paper or corrugated cardboard that can double as food. Add a pound or more of hungry worms (figure as much as $25 per pound, which works out to about 1,000 earthworms) and you're in business.

"One pound of worms can easily handle 3 pounds of waste per week," Benoy said.

Worm composting can be fun and easy, but it's not simply a matter of digging up a few garden-variety night crawlers from your backyard, she said.

"Night crawlers tend to be solitary and won't reproduce in bins," Benoy said. "Red worms (Wigglers or Eisenia foetida) are hardy, easy to handle and best for composting."

Worm bins can be placed in the home or out, but do best where air can circulate and temperatures are kept between 55 and 75 degrees. The operation is odor-free, but you can raise a stink by overfeeding or adding too much water. Worms like their surroundings about as damp as a squeezed sponge.

"There shouldn't be any smell coming from a worm bin except like from a rich, brown dirt," Benoy said. "The bin has gone anaerobic (without oxygen) if it stinks like rotten eggs. It's not properly draining. There's too much moisture. The bacteria will die."

Castings go farther when brewed up as worm tea. Scoop some into a net bag or pantyhose, drop that into a water-filled container, add a dollop of molasses to nourish the bacteria, and then mix it for a day or so using an inexpensive aquarium air pump.

"Worm tea is the strongest organic fertilizer there is," said Curtis Thomsen, program manager for the Los Angeles County Smart Gardening Program.

"It has a ton of good uses, but primarily as fertilizer, herbicide and compost. Worm compost and worm tea are a great one-two punch. They add bacteria to the soil, aid in root development, help get rid of fungus and mildew, enable you to cut back on watering, and get rid of pests like aphids and black flies."

Worm castings and worm tea can increase garden productivity anywhere from 20 percent to 200 percent, Thomsen said. "I've personally seen 12 tomato plants grow to a height of 12 feet and produce 200 pounds of tomatoes per bush," he said.

Online:

For more about worm composting, try this Smart Gardening resource from the County of Los Angeles Department of Public Works: http://dpw.lacounty.gov/epd/sg/wc.cfm.

You can contact Dean Fosdick at deanfosdick(at)netscape.net

On the Net:

http://dpw.lacounty.gov/epd/sg/wc.cfm: http://dpw.lacounty.gov/epd/sg/wc.cfm