Small-Space Gardening: Build a Tiny Raised Bed

Limited yard space doesn't mean you have to forgo growing seasonal vegetables. It just means you need a simple plan. A raised garden bed, even as tiny as 4x4 feet, yields robust results. "It allows you to garden just about anywhere you want," says Greg Stack, extension educator of horticulture at the University of Illinois. "I've seen them built over soil, grass and concrete slabs."

Designate a different crop to each square-foot area. After harvesting one crop, plant another in its place. These small plots require little maintenance (they typically harbor few weeds), so you're more apt to stick with it for three seasons of fresh, healthy eats.

Build a raised bed

Find the right wood Build your bed with 2x6-inch boards, such as naturally rot-resistant cedar or composite lumber. If you want pressure-treated wood for its low cost and easy maintenance, use ACQ-treated (alkaline copper quaternary) lumber, which doesn't contain arsenic. For the DIY beginner, home improvement stores offer raised-bed kits.

Soak up the sun Site away from trees; veggies need at least six hours of sun per day.

Add rich dirt Well-drained soil with loads of organic matter is key, Greg says. Find a local source offering a soil mix containing one-third each topsoil, compost and coarse sand (or mix your own). Cover with an inch of mulch to discourage weeds. If the bed is built on concrete, soil should be 12 to 18 inches deep. Otherwise, six inches is sufficient.

Pick plants wisely "To make the best use of space, look for compact or dwarf varieties," says Rosie Lerner, horticulture specialist at Purdue University. Start with cool-season veggies, such as lettuce and spinach; replace with summer crops, like green bush beans and determinate tomatoes. In the fall, switch back to cool-season plants. "That will double or triple the amount of production in a small garden," Rosie says.

Avoid space hogs Sweet corn and squash take up lots of space. If you want to plant vining crops, like peas and beans, train them up a trellis, Rosie says.

Seasonal switches

Succession gardening (planting different crops at intervals in the same space) guarantees a bounty of produce. Here's how many to plant in each square-foot area.

Spring

Broccoli–1 to 2

Cabbage–1 to 2

Carrots–16

Cauliflower–1 to 2

Leeks–9

Lettuce–4

Onions–16

Peas–8

Radishes–16

Spinach–9

Swiss chard–4

Summer

Beets–9

Bush beans–9

Eggplant–1

Peppers–1 to 2

Tomatoes–1

Fall

Same as spring, minus peas, plus Kale–1 to 2