GARDENING : Make Your (Raised) Bed--and Plant in It

When Nola Skyler used to harvest carrots, the bottom halves remained in the hard, compacted earth. Now, thanks to the raised-bed garden she has installed, the soil is loose and workable, and the carrots come out whole.

“My root crops grow better now because they can easily penetrate the soil. As a matter of fact, all of my crops have improved,” says the Huntington Beach resident, who writes the newsletter for the Horticultural Society of Orange County. “In one area of the yard, I’m growing some plants on ground level. The plants in the raised bed are doing 100 times better.”

Similar to giant containers, raised beds simplify gardening.

“One major advantage to raised-bed gardening is that the soil you build your beds up with is much looser and easier to work in than our native soil,” says Kelly Kong-Green, manager of Flowerdale Nurseries in Costa Mesa.

Once a raised-bed garden is installed, gardeners no longer have to rototill the soil every spring.

“There’s no need to use machinery on raised-bed gardens,” says Ken Denham, a member of the Orange County Organic Gardening Club, who has gardened in raised beds for more than 10 years. “Your soil sits aboveground and remains light and fluffy.”

And light, fluffy soil is extremely important.

“The looser your soil, the healthier and more productive your plants will be,” Kong-Green says. “Loose soil has better airspace. Plants grow more vigorously when the roots don’t have to struggle to penetrate hard earth.”

Another big benefit of raised-bed gardening is the comfort it provides the gardener. Most raised beds range from 1 1/2 to two feet in height, making bending over unnecessary.

Gardeners can build a ledge onto the raised bed for sitting or they can pull up a chair and garden from it. This is especially good for people with back or knee problems.

Raised-bed gardening also saves room.

The beds can be constructed in any shape or size that fits the space requirements. It’s also possible to plant crops closer together and get a larger harvest from the same space. Many crops can hang over the bed’s edge, which is attractive.

“It’s actually healthy to plant more closely because you create a humid microclimate among the plants,” says Carrie Teasdale, an organic gardener who lives in Fullerton. “Plant leaves provide shade, which conserves water and promotes growth. Salad greens especially benefit from this climate. You can plant them in the shadow of larger vegetables.”

Because the garden is confined, there is a smaller space to weed.

Installing a raised-bed garden is a simple procedure.

First, choose an appropriate site for the garden, perhaps where a garden already exists. “Whatever you do, realize that you’re installing a permanent garden, so take some time selecting your site,” Denham says. “Put it in an area close to the house so picking vegetables is easy.”

Generally it’s best to place the bed in full sun, especially for tomatoes, squash, peppers and eggplant.

“Without sun you don’t have enough energy for many vegetable crops to produce,” Teasdale says. “While there are some crops that can’t tolerate direct sun in the summer--such as salad greens, beets, carrots and chard--you can always provide them with shade by planting them on the north side of sun-loving crops or covering them.”

Beds are made out of a variety of materials.

“Most people use wood, but you can also use block cement or stone,” Teasdale says. “Stone warms up and holds heat, which is great for plants in the spring, fall and winter. It does get very hot in the summer, though. Plant warm-weather crops early so they will grow large enough to shade the stone on hot days.”

Cement or anything containing cement (concrete blocks, stucco) are also useful, however, according to Teasdale, it can release small amounts of alkaline substances into the soil, which can upset the soil pH and may be toxic in the long run.

Wood is a popular choice for raised-bed construction because many people find it attractive. It does break down over time, but adds helpful carbon to the soil. For beds that last, use redwood, which holds up to the wear and tear of watering.

When constructing a raised bed, make it no wider than four feet, which will allow you to reach inside and work. You don’t want to walk on the soil, because that will compact it.

“The standard width is four feet, although if you are a petite person, you may want to make it three feet wide,” Teasdale says. “Generally they are longer than they are wide. Make yours as long as you want, depending on the space available.”

To construct a wooden raised bed, cut 2 x 6’s or 2 x 8’s the desired length and width of the raised bed. Nail them to vertical 2 x 4 posts which are placed in each corner. Denham nails two 2 x 4 posts together in each corner and then inserts 2 x 6’s or 2 x 8’s inside of this structure. If your bed is longer than five or six feet, Teasdale suggests inserting posts every four feet so that the bed doesn’t bulge and strain in the center.

Denham also adds chicken wire to the base of his raised bed and up the sides, attaching it to the wood. This protects his garden from underground pests such as gophers.

When constructing a raised bed, allow for drainage. “Once water passes through the soil in your garden and hits our native soil, it will just sit there, unless you have a place for it to drain,” Kong-Green says. “An easy way to do this is to drill holes on the sides of the bed walls at the bottom.”

It’s also handy to be able to attach row cover, plastic or shade cloth to the bed. Row covers keep birds and pests away from plants, black plastic warms the surface of the soil and air so that you can grow warm-weather crops in colder months, while shade cloth keeps the garden cool, allowing you to grow crops such as lettuce in the heat of summer. Old window screens can also be used in place of shade cloth.

To attach the covers, install corner posts that are taller than the rest of the bed. Row cover is light and can be tied to the posts, but shade cloth, screens and plastic may need extra support. To provide this, Teasdale attaches strong string around the four posts and then crosses it in the middle to make an X.

After the bed is constructed, fill it with good topsoil. “Purchase topsoil from a landscape company that has a good reputation,” Teasdale says. “You don’t want fill dirt that was excavated from a building--or worse--a gas station.”

Kong-Green suggests consulting a nursery for a landscape company near you that sells the type of topsoil that is good for your area.

Add compost and fertilizer to the topsoil mixture in the bed. Water it and wait a few days before planting, giving it a chance to settle.

At least once a year, add more compost and fertilizer. Some gardeners rejuvenate the soil every time they replant, finding that added compost and manures keep the bed loose and rich in nutrients.

Make sure not to over-water your raised bed because too much moisture can lead to structure deterioration. “Before you water, stick a finger into the soil,” Kong-Green says. “Don’t water if the soil is still moist.”