A New System -- Strawberry Plasticulture
Strawberry plants can also be grown on raised beds covered with black plastic. When black plastic is used, planting stock can be either dormant plants or plants grown from rooted runner tips (called plug plants). With this system, trickle tape under the plastic for irrigation and row covers (lightweight spun-bonded material) for winter protection will also be needed. Plants should be grown in a protected location.
Plug plants are planted through the plastic in late summer or early fall; dormant plants are planted in July. Plants are spaced more closely than usual at about one foot apart in staggered double rows. Row covers are placed over the beds in mid-October to increase fall growth, and runners produced during the fall should be pinched off. Bloom and harvest begins earlier than usual in the spring, which means that frost damage is of greater concern.
About 1.5 pounds of 10-10-10 fertilizer per 100 square feet should be worked into the bed prior to planting. After planting, water-soluble fertilizers need to be used since granular fertilizers cannot be applied with the plastic in place. Three ounces of a 20-20-20 water-soluble fertilizer per 100 feet of row should be applied in the spring in each of three applications (9 ounces total) a week apart, starting when the plants make good growth. Dilute the fertilizer according to package directions to avoid burning the plants. Decrease or omit fertilizer applications if growth is overly vigorous.
Plantings can be kept for a second year of harvest. After the fruit production ends for the season, trim off the plants as close to the plastic as possible and allow them to regrow. Keep the plants watered and fertilize them with 9 ounces of 20-20-20 soluble fertilizer in late August, again decreasing amounts if growth is very vigorous.