Taking Veggies to New Heights

Imagine a vegetable garden in which seeds sprout quickly, carrots grow long and straight and the soil is a pleasure to work in. A garden free of snails and gophers. And one you can make yourself.

Picture raised beds.

Using just about any kind of building material, you can easily make a small raised bed yourself, fill it with the best soil and amendments, and virtually pest-proof it with copper strips that repel snails or metal bottom screens that exclude gophers and moles.

“It’s the way to go,” says Janie Malloy of Home Grown in Pasadena, who has installed dozens of raised beds for clients.

The folks at the Common Ground gardening program would seem to agree. Every week they build a few more raised beds for community gardens in the Los Angeles area. In these gardens, everything from flowers to herbs is grown in raised beds, but they really do wonders for the finicky vegetables, especially when you’re trying to garden in poor soil.

In school gardens they’ve even managed to garden on blacktop, said Rachel Mabie, the urban horticulture advisor for Common Ground. They stack landscape logs four high, log-cabin style, to make vegetable beds about 16 to 18 inches tall, filling them with imported soil.

In home gardens, Malloy, who designs and installs organic vegetable gardens, makes much shorter beds with 2-by-6 boards. Instead of bringing soil in, she improves what’s already there by adding lots of compost. This makes it loose--almost fluffy--and easy to work in. It also ends up a few inches higher, partially filling the raised bed frames she sets on top.

Eighty percent of the gardens she installs are in raised beds. “I love them.” she says. “They’re efficient, attractive; maintenance is low and they’re easy to water.”

In home gardens or community gardens, raised beds make vegetable gardening neat and attractive, nice enough for the frontyard. They can even be arranged in tidy formal patterns--much like old Dutch or French potagers or early American kitchen gardens--to become the centerpiece of the garden.

They make vegetable gardening a year-round, every day activity, rain or shine. Liz Doonan of La Canada Flintridge has decomposed granite paths between her raised beds. “I use them constantly; every day in fact,” she said.

If you mulch the paths between the beds with shredded bark, gravel or decomposed granite, you can harvest on rainy days, or after irrigation, without getting your feet muddy, and because the beds are elevated, the soil doesn’t get soggy.

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And you can build them out of just about anything from concrete blocks to timbers. “We’ve tried all sorts of materials and designs,” said Common Ground’s Mabie, but they’ve settled on beds made from stacks of 4-by-4s or landscape logs.

Railroad ties and treated timbers last longer than plain wood, but some object to the chemicals used to treat the wood.

Concrete blocks or large river rocks also work and last forever, but wood is the easiest to work with. After a few years, ordinary wood will begin to rot, but Malloy makes hers of redwood and several are now 7 years old.

Simply nail boards together and bury a little of the bottom in the ground so the beds don’t leak soil at the base. Burying a bit also helps keep the sides straight. Malloy uses wood stakes or copper pipe outside hers to help hold them in place.

If you use 2-inch-thick boards, try capping them with horizontal 2-by-4s so you have a wider ledge to kneel or sit on while working.

Most beds are 4 feet across so the centers can be reached from either side. Any wider and it’s hard not to constantly step inside the beds, which compacts the soil and defeats at least part of their reason to be.

Three feet is another popular width, but Mabie points out that lumber is often sold in 8-foot lengths, so cutting a board in half gives you two 4-foot end pieces to work with. Beds are usually 8 feet long for the same reason. Most gardeners find several beds this size make a large enough garden.

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Raised beds are best for smaller crops, but many contain tomatoes and corn. Trellises for beans and peas and even cucumbers can be nailed to the sides. Pumpkins and winter squash generally grow too big for raised beds and are better grown elsewhere, though even they can be planted in the beds if gophers are a problem.

If you have really lousy soil, you can make tall beds, filling them with topsoil and ignoring the soil underneath.

Use 2-by-12s or 2-by-10s or stacks of sturdy 4-by-4s.

Peter Beaudoin, with Common Ground, made 18-inch-tall raised beds of 4-by-6s stacked three high for a community garden in Long Beach that has an impossibly heavy, sticky clay soil. He filled these big beds with imported topsoil and held them together by overlapping each layer, pounding in 8-inch spikes after first pre-drilling starter holes.

Mabie cautions that you want to be a careful shopper when ordering or bringing in topsoil. A sandy loam is best, but if it’s too sandy it will dry out quickly after irrigations. If amendments have been added, make sure they are thoroughly composted, or that nitrogen has been added, so they do not steal this important nutrient from the plants (used in the decomposition process). No matter how good the topsoil is, you’ll probably want to augment it with bagged soil amendments or compost, plus fertilizer.

In fair to good soils, simply improve the existing soil with amendments or compost, plus fertilizer. You can add lots of amendment or compost to make the soil soft and fluffy, starting with a 6-inch layer thoroughly tilled in to a depth of about 18 inches. Add even more if the soil isn’t easy to work. Always work the soil when it is damp, not wet or dry.

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To exclude snails, nail special copper barrier strips along the top of the outside of the beds, then fold the flaps over the wood, so they are flush with the wood and face in. The strips are designed to face outward but could be hazardous to gardener’s legs in this position. If you add a 2-by-4 cap to the beds, you can tack the copper strips under the ledge of the 2-by-4, so the folded copper is facing out.

If no vegetables hang over the side (becoming siege ladders for the snails), you exclude them, Malloy said.

One source for these strips is the Natural Gardening Co. (217 San Anselmo Ave., San Anselmo, CA 94960, [707] 766-9303) though you can find them at some nurseries. A 20-foot barrier costs about $15.

If gophers or moles are a problem in your garden, make the sides of the beds 12 inches tall (gophers can climb into a bed any shorter) and then cover the bottom with half-inch aviary wire or galvanized hardware cloth with half-inch or quarter-inch openings.

Many simply water the beds by hand, but installing drip lines or using pop-up sprinklers with small radius nozzles, inside the beds, makes watering a snap. Robert Kourik’s book “Drip Irrigation” (Metamorphic Press, P.O. Box 1841, Santa Rosa, CA 95402, [707] 874-2606) has a section devoted to raised beds that details a nifty removable system.

With the soil improved, sprinklers in place and snails and gophers excluded, you will quickly discover why Malloy insists this is the “only way to go.”