Grown for their tart, red fruit, strawberries (Fragaria ananassa) make a productive addition to the landscape. Everbearing varieties produce berries in the late spring and late fall, day-neutral varieties bear sporadically throughout the growing season, and June-bearing varieties produce a single, abundant crop in the late spring. Strawberries will grow as perennials in U.S. Department of Agriculture plant hardiness zones 5 through 8 and annuals in zones 9 through 10, where they require full sunlight and fast-draining, nutrient-rich soils with a pH of 5.3 of 6.5. Gardeners with poor soil or minimal space may grow strawberry plants in concrete blocks.
Select a planting site that receives at least 6 to 10 hours of direct sunlight each day. Pull weeds and clear debris from the site, cleaning an area 32 inches wide by 36 inches long.
Lay a 32-inch-by-36-inch square of wire or mesh screen on the cleared site to prevent the soil from falling out of the concrete blocks. Place concrete blocks in 6 parallel rows across the screen each consisting of two blocks. Push the blocks together so that their sides and ends touch.
Pour 1 to 2 gallons of potting soil into a 5-gallon bucket. Add a 10-10-10 nitrogen, phosphorous, potassium slow-release granular fertilizer to the bucket at a rate of 1/2 tablespoon per 1 gallon of soil. Stir the soil and fertilize together with a trowel.
Fill one of the corner holes one-half to two-thirds full of the potting soil. Mound the soil up in the center of the hole.
Select a strawberry start, and cut its roots back to a length of 4 to 5 inches with pruning shears. Place the start in the soil-filled hole, spreading its roots out around the soil mound. Adjust the depth of the soil if needed to position the point just below the plant's crown 1/2 inch below the top of the hole.
Add soil to the hole, filling it to 1/2 inch below its top. Tamp the soil down around the plant's roots. Do not over fill the hole or bury the strawberry start's crown. Repeat the planting process to plant one start in every other hole of the concrete block bed, creating a checkerboard-like pattern. Mix more soil as needed.
Attach a water wand to the end of a garden hose. Move the wand slowly in a back and forth pattern once along each row in the block bed. Repeat this process two to three times to ensure that the soil in the blocks holes becomes moistened evenly and completely.
Water the strawberries when the top 1 to 2 inches of soil becomes dry. Follow the same watering pattern as before, applying a total of 1/2-inch water to each hole. Never let the soil dry out completely or become soggy.
Mix 1 teaspoon of 15-30-15 nitrogen, phosphorous, potassium water-soluble fertilizer with 1 gallon of water in a watering can. Apply the fertilizer three months after planting. Fill each hole containing a plant full of the solution. Wait for the liquid to soak into the soil. Fill each hole a second time. Fertilize the plants in this manner every 7 to 14 days throughout the remainder of the growing season.
Cut off flowers as they appear on June-bearing strawberries in the late-spring to early summer. Remove flowers on day-neutral and everbearing varieties until mid-summer. Make each cut with the pruning shears 1/4 inch above the point where the flower stem attaches to the plant. This process will encourage the plants to develop a strong root system and additional fruit-bearing stems.
Cover the plants with a 3-inch layer of straw in the fall, after temperatures drop below 30 degrees Fahrenheit but before they reach 20 degrees Fahrenheit or colder. Build the mulch up around the sides of the concrete blocks sitting at the bed's perimeter to create a layer of insulation for the roots and side shoots. Remove the straw in the early spring once the strawberry leaves begin to turn yellow.
Replace the strawberry plants every three to five years. Lift the concrete blocks up, and push the soil and plants out of its holes. Rake up the discarded material, and place it on a compost pile. Replant the strawberry bed using new potting soil and new plant starts.