SIZE: 4 by 12 feet

TIME: 2 days to plant, plus prep

COST: $175

Shoulder-to-shoulder planting in double-dug soil delivers more food per square foot than any system we've ever used. Roots grow down instead of out, so you can space plants closer together and still get high production. In turn the close spacing shades out weeds, so they don't become major problems as they do in a more open garden.

The system demands extra-deep soil preparation, done by double-digging with a garden spade (with a squared-off blade). Dig out the top 10 to 11 inches of soil and pile it by the side of the bed. Then loosen the soil in the bottom of the bed another spade-length deep; simply dig and turn that bottom layer of soil in place with the spade, or (in traditional English garden fashion) loosen it with a spading fork.

When you're done, put the top layer of soil back into the garden bed, mixing 1/3 to 1/2 yard of compost into the whole bed. This process is very hard work but extremely rewarding.

PLANT LIST
(numerals indicate number of plants; spacing given in inches)

A. Pole beans, 24 seeds (2 tepees); 4"

B. Sunflowers, 6 (grouped); 18"

C. White cosmos, 12 (grouped); 6"

D. Tomatoes, 4; 21"

E. Parsley, 10; 6"

F. 'Tricolor' sage, 1; 15"

G. 'Golden' sage, 1; 15"

H. Chives, 2; 6"

I. Zucchini, 2; 15"

J. Sweet basil, 2; 6"

Preparation, planting

A FEW DAYS AHEAD

1. Choose a sunny spot with access from all sides.

2. Order soil amendment, and if you're making the keyhole garden and don't want to hand-dig it, rent a rotary tiller.

3. Order seedlings. Choose varieties suited to your region (nurseries and garden centers usually have these). The varieties we list here are the ones we used in our Menlo Park, California, test garden. Also buy bamboo poles and tomato cages.

4. Get rid of weeds.

WEEKEND, DAY 1

1. Prepare the soil. Follow directions above or directions for Keyhole vegetable garden.

2. Erect tepees to support pole beans: Tie four 8-foot bamboo poles together 6 inches from one end, then stand upright.

3. Water the bed thoroughly, then let it settle overnight before planting.

WEEKEND, DAY 2

1. Set out most plants in a diamond pattern, spacing as indicated on plant list.

2. Plant pole beans on tepees. At the three bean seeds.

3. Support tomatoes with cages, putting one plant in the center of each (as it grows, it will fill the cage).

4. Snake soaker hoses through the beds as soon as seedlings are planted.

5. Apply mulch to keep down weeds and conserve water. We used Coco Grow mulch, but if you garden in the mountains or in a cool-summer climate, substitute black plastic mulch, which will make the soil warmer.

6. Fertilize at planting time with a spray of fish emulsion. Repeat about every two weeks. Stop feeding fruiting plants such as tomatoes, beans, and peppers as soon as they start flowering, but keep feeding leaf vegetables through the season. For an added boost, feed all plants with a dose of organic, complete vegetable fertilizer (a 5-5-5 formula) twice during the growing season.