Master Gardener in training: Worms are an easy-to-love fertilizer


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(This is one in a series of posts in which Jeff Spurrier shares his experience from a Master Gardener class.)


There’s something elegantly basic about a worm -- no lungs, no ears, no eyes, no brain, simply a feeding tube that eats garbage and excretes high-priced fertilizer in between non-stop mating.

I’ve had my worms about 10 days and even though I know they can’t hear, when I go out with their finely diced honeydew rind, I croon to them softly, “The worms crawl in, the worms crawl out …”

This week’s worm theme began with Curtis Thompson from the L.A. County Department of Public Works Smart Gardening Program, who talked to the Master Gardener class about worms and composting.

I didn’t need to be convinced about the joys of composting; being an essentially lazy gardener, I welcome any excuse not to haul the yard’s detritus down 65 steps to the street where I’ll never find an empty green bin anyway. Instead I just heap it all up in a pile -- the slightly inelegant name for what some neighbors might call a fire hazard -- and pay attention to my mix of roughly 50-50 green/brown, keeping it moist but not soggy, and, like a grudge, stirring every day or two. A well-maintained pile can produce finished compost in six weeks, Thompson said. A pile that’s dry or matted could take a year or more.

Composting with worms, on the other hand, requires a bit more attention but has a more dramatic payoff. There are more than 2,700 types of earthworms, according to the Worm Digest, but African red wigglers (a.k.a. tiger worms, garlic worms, manure worms, or brandling worms) are most commonly used in bins. A starter population of a half-pound (200 to 300 worms, or about two handfuls) goes through about five pounds of well-chopped kitchen scraps a week, a process that can be speeded up by first freezing the food (thus breaking up cellular walls). They can be fed daily or less often, and the finer the dice, the more the worms eat and the faster they reproduce. Avoid wheat, citrus, garlic, bones, dairy and oil. They’re fine with onions, shredded newspaper, coffee grounds (and paper filters), tea bags (remove the staple). They love melon, including the rind.

In about two months the worms will have produced a harvestable amount of vermicast, a manure that looks like soil but has five times as much nitrogen and seven times as much phosphorus as is typically found in topsoil. When using, mix one part castings to two parts compost (or potting soil). If it’s for orchids or tropicals, reverse the formula.


To harvest the castings after a few months, gradually train your worms to migrate to one end of the bin or the other by alternating your weekly feeding sites and scooping up the residue from beneath past food zones.

Worm tea (which sells for $25 a gallon online) is either collected as liquid runoff from a bin or made from soaking castings in water. Strain and dilute the straight tea from a bin with water, 6 to 1. It’s safe for use as a spray on flowers, trees, shrubs and veggies. Besides giving plants an easily digested shot of nutrients, it also repels mites, whitefly and aphids, conditions the soil and works as a fungicide. Thompson says worm tea can also help reinvigorate oak trees with fungus or pines with beetle infestation.

The two major pests you have to worry about are ants and soldier flies, both of which can decimate a worm bin. With no lungs, worms breathe through their skin and thus are susceptible to suffocation from too much water or too much heat. Like many of us they like it cool, dark and moist. And ant-free.

The Smart Gardening program holds workshops on composting and vermiculture where you can get one of their two-tier stackable bins, above (with a spigot for tea) along with your starter population ($65). While three inches of torn-up newspaper can be used for bedding, coconut coir (available at nurseries in a brick, at left, or at the workshops) is preferable since it’s less likely to get soggy or dry out. You could also build a bin from just about anything that has at least 10 drainage holes and a fly-proof cover and can be kept at a temperature of 60 to 80 degrees F. (Metal bins, for this reason, are a bad idea.) Never put water in a worm bin. If you need to moisten the bedding, use a spray bottle.

Worms don’t like to be handled, but every once in a while I sink my hands into the bedding and let them slither blindly over my fingers. Try doing that with a compost pile.

-- Jeff Spurrier

Recent and related:

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