Popular mechanics 2009 04 extract

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Grow Up

RAISED B E DS TA K E TH E HASSLE OUT OF HORTICULTURE.

BY FIONA GILSENAN

Experienced gardeners use raised beds to side ep a long li of gardening challenges. ese controlled experiments in plant parenthood are so easy, in fa , that they’re also well-suited to novices picking up a shovel for the fir time.

Bad dirt is out, because you fill a raised bed with a cu omized soiland-compost blend. Drainage is built into the bed walls, which hold the soil in place to keep erosion in check. Greater exposure to the sun warms the bed, which allows more plant diversity and extends the growing season. Plants can be

PHOTOGR APH BY JODY ROGAC

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spaced closely together, so yields go up, water-use efficiency is maximized and weeds are crowded out.

Finally, raising the soil level by even a foot reduces the back-bending effort needed for jobs such as planting, weeding and harve ing.

Beyond the ease is the control—as you grow your favorite foods, you feed and soak your plants with just what they need for optimum growth.

A raised bed is most productive and attractive as a bottomless frame set into a shallow trench. The sides can be almost any durable building material, including rock, brick, concrete and interlocking blocks.

Watering troughs or claw-foot tubs can work, as long as they have the capacity and drainage.

But by far the mo common material for raised beds is lumber. e major caveat, since raised beds are often used to grow edibles, is to eer clear of wood preserved with toxins. Avoid creosote-treated railroad ties; opt in ead for naturally rot-resi ant cedar or redwood. e EPA considers wood infused with alkaline copper quaternary (ACQ) to be safe for food crops, but if you use this pressure-treated wood you may want to line the bed interior with landscape fabric—an air-andwater-permeable screen—to prevent soil conta . Whether using pressuretreated or naturally rot-resi ant wood, put the bed together with galvanized or ainless screws or bolts.

level. In general, a north–south orientation takes full advantage of available light. Stay close to the kitchen, but avoid sites shaded by the house or beneath messy trees. Leave at least 18 in. between beds for walkways, or 2 ft if you need room for a wheelbarrow or lawnmower.

Planning, Building

To prepare the site, get rid of turf and weeds. Outline the bed dimensions on the ground with chalkline or

Miter lumber at 45 degrees to make the cap railing—a place to sit while weeding and harve ing.

Bed covers ward off inse s and keep plants warm in cool weather.

string, then dig with vertical strokes along the outline, ju deep enough to bury about half of your fir course of lumber. Raised beds are designed so water trickles down, eliminating mo of the problem of poor drainage. But if your only viable location is bogged in a marsh, you can prevent the “bathtub effe ” by digging a few inches deeper and putting a layer of coarse one or pea gravel in the excavation. (You can also in all perforated drainage pipes in trenches under or around the bed, or ju drill weep holes at the base of the sides.) Likewise, if there is no turf between your beds, put down some landscape fabric and cover it with pavers or a layer of gravel to improve drainage—a er running out in the rain for a fresh bell pepper, you’ll appreciate the mud-free shoes.

Level the earth or gravel layer at the bottom of the bed, then put down a layer of weed-suppressing landscape fabric that extends to the outer edge of the wooden frame. Now is also the time to think about pe control. “ e rich soil in a raised bed has worms and

Use galvanized pipe raps to mount 1-in. PVC pipe inside the bed walls. Cut ½-in. flexible PVC tubing twice as long as the beds’ width. Bend it, mount it and clip a cover in place.

Location, Location

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A 3 x 6– bed should be wide enough to support sprawling tomatoes, but narrow enough to reach easily from both sides. e ideal height is 1 to 2 tall—you can go taller, but you need a considerable amount of soil to fill a 3-ft-high bed. If possible, build more than one bed, which makes it easier to rotate crops and meet the watering 6 needs of specific plants. Aligning beds in raight rows simplifies the in allation of an irrigation sy em.

Finding a flat spot spares a lot of digging—you want the walls to be

other delicacies that attra moles, and gophers and voles relish young veggie roots,” Sausalito, Calif., garden designer Tom Wilhite says. “To keep out burrowing pe s I always recommend a bottom layer of hardware cloth”—a mesh grid of eel or galvanized metal.

Build each wall separately, then fasten them together and put the bed into position. Raised-bed builders often sink posts into the ground for stability, either at the inside corners of the bed or halfway along the side walls. These help hold the bed

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in place, but can also reduce the outward pressure that a full bed exerts on the frame, which can dislodge the lumber after a single season. A cap railing that runs around the top of the bed ties everything together. Plus, it provides a handy place to set down gardening tools while working, or, when you’re done, a seat to admire the fruits of your labor.

Greenhouse Effe

A simple framework of hoops and a lightweight cover can extend your growing season in cool areas, conserve moi ure in dry areas and prote plants from birds or inse s. Use clear polyethylene film to raise soil and air temperatures in early spring or fall—to get an early art on heirloom tomatoes, for in ance, or to try your hand at exotic squashes. But be careful not to bake your plants on warmer days. Remove the cover or slit vents in it to avoid excessive heat buildup.

For pe control, cover the bed with bird netting or with gauzelike fabrics known as floating row covers, which keep out flying inse s but let in both light and air.

½-in. Poly Tubing

Drip Emitters

End Caps

Shutoff Valve

e simple dripirrigation setup uses flexible ½-in. poly tubing.

It in alls easily, it’s inexpensive and it can easily be repaired if damaged.

Drip emitters spaced evenly at 12-in. intervals send water to the plants’ roots throughout the bed. In all spray emitters to give leafy greens a rinse above the soil’s surface.

Spray Emitter

Don’t fill the bed with dirt from the garden. In ead, use peat moss, compo or a soil mix for planters.

Use a 2 x 4 to level the soil, then plant.

Automate, Irrigate

Once you add an automatic watering sy em to your raised-bed garden, you’re free to plant, weed and harve .

A simple micro-irrigation setup ensures that plants get water consistently— especially important for seedlings and leaf crops such as lettuce. “ e sides of raised beds heat up quickly in the sun, baking the moi ure out of the soil,” Wilhite says. “Irrigation delivers the water evenly and gently. You can set your timer to water early in the morning—less will evaporate, and you resi disease.”

A basic setup arts with a faucet or hose-bib attachment that is essentially a series of valves that prevent back flow into the plumbing, filter the water and control the water pressure.

These valves are designed with 1-in. or ¾-in. conne ions. From these, attach supply lines of flexible ½-in. poly tubing. e tubing’s accessibility makes it easy to check for leaks and repair damage from pun ures or bur s. To prote the tubing, bury it a few inches and cover the line with mulch.

Lay the tubing along the beds in lines 12 in. apart. Fit se ions together with compression elbow and T-fittings.

In all drip emitters at 12-in. intervals along the length of the tubing for even delivery of moisture to plants. Lowvolume sprayers or mi ers on risers can also be used, but these lose more water to evaporation. Close the ends of each line with hose-end plugs and caps. en sit back and let the sy em FC water for you.

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