Site preparation is particularly important when planting a strawberry patch as the plants will remain in the same spot for years. Choose a sunny, weed-free location– north-facing if possible — and away from trees and other shade-producing plants. Use an established garden space for your patch rather than tearing up sod where grubs and other root-attacking pests may reside.
Do NOT put your patch in an area where tomatoes, eggplants or other members of the nightshade family have been recently planted. These plants, as well as other berries, can harbor Verticillium, Fusarium wilt, and other fungi-caused diseases that persist in soil for up to four years.
Strawberries need constant moisture but don’t like standing water. They prefer sandy loam that is well-drained but with good water retention. Poor-draining, clay soils can be improved with organic peat moss or coconut coir and other organic materials. Prepare the bed the fall before planting by working lots of manure, grass clippings, shredded leaves, straw, and other organic material into the soil and allowing it to decompose over winter.
Plants do best with a pH reading between 6.0 and 6.5 but will tolerate soil pH as high as 7.0 (neutral). Test your soil in the fall before planting and add dolomite lime if the soil is too acidic and pH needs raising. If the soil is too alkaline, use elemental sulfur to raise the level.
A week or so before setting out plants, apply a balanced organic fertilizer or compost to the patch.
How to Plant
Plant strawberries in the spring as soon as the soil can be worked. The two most common methods of planting strawberries are the matted-row system and the hill system.
The matted row system, commonly used with runner-producing June-bearing varieties, spaces mother plants up to 60cm apart in rows up to three feet apart. After the mother plants are established, runners are allowed to set in the space between plants (remove runners and blossoms during the first season to encourage rooting and plant growth).
These runners can be pinned at 12 inches from the mother plant with additional runners pruned as they appear (“space-matting system”), or can be allowed to set where they will without pruning. The space-matting system makes for strongest plant growth and most productive harvests.
The hill method, most often used for everbearing and day-neutral berries, is best suited for raised beds. Plants are set 30cm apart in staggered double or triple rows. Runners are pinched and not allowed to set. June-bearing varieties can also be grown this way but will have fewer productive years.
Choose cultivars that are certified pest and disease free. Trim any runners and blossoms as well as any damaged roots or those over 15cm long. Plants should be set with the crown half in and half out of the soil. The roots extending from the bottom of the crown should be well beneath the soil line. The leaf stems emerging from the top of the crown should be well above the soil.
Make the hole deep enough to accommodate the roots without twisting or bending. Transplant in the late afternoon to avoid heat stress and drying out. Water each plant as soon as it’s set in the earth.
To encourage growth, trim all blossoms and runners from June-bearing plants through the first season. This will result in stronger harvests come the second year. Pick blossoms from neutral and everbearing strawberries during the first month after planting in the garden, allowing the second show of blossoms to fruit for a fall crop.
Neutral and everbearing strawberries are sometimes offered as seed. Allow the seed a dormancy period by placing it in a bag with peat or coir dust and placing in the freezer for at least two weeks.
Four to six weeks before the last frost, take them out of the freezer and allow to sit overnight. Start the seeds in potting trays filled with moist, slightly acidic soil, in holes 1cm deep and 15cm apart. Strawberry seeds are tiny.
Tweezers can help in the planting and two or three seeds should be placed in each hole. Seeds can take two to four weeks to germinate, depending on soil temperature (60 – 70 degrees is ideal). Keep soil moist during the germination process.
Thin seedlings as they emerge to provide 15cm between plants. When they’ve developed three true leaves, transplant seedling carefully to 8cm pots using a gardening knife or narrow trowel to completely extract roots and the soil around them. Provide your transplanted seedling with eight hours a day of light and keep moist until they are ready to be set in the garden.
Tip: Strawberries do NOT compete well with weeds, which can easily take over a patch. Start with weed-free soil and remove any weeds that do surface as soon as they appear.
Harvesting and Storage
Ripe berries are ready to harvest four to six weeks after blossoming. Pick June-bearing strawberries every other day to avoid lost or rotting fruit. Never pull them from the plant. Instead, snip them carefully near the crown of the berry. Leave crowns attached unless the berries are to be eaten immediately.
Berries, depending on ripeness, can be kept a day or two without refrigeration (best) and three to four days in the refrigerator. Berries also freeze well and can be used frozen for breakfast smoothies or allowed to thaw for use in sauces, jams and baking.
Insect & Disease Problems
Strawberries, though relatively pest free, can be damaged by slugs, aphids, spider mites, and other pests. Keep a close eye on your plants. Look for holes in leaves that indicate the presence of slugs, then inspect plants a night with a flashlight and handpick any snails and slugs you find. Use an organic slug bait or traps to reduce slug numbers. Copper barriers can be used to keep slugs away from plants. Use organic insecticidal soap to control mites and aphids whose presence is indicated by yellow, curling, and stippled leaves.
Wilted plants can indicate the presence of white grubs (the larvae of the June beetle), root weevil, wireworms, or other grubs. To control them, apply beneficial nematodes to soil after removing the wilted plants.
Use row covers or netting to protect the berries from marauding birds.
Preventive measures, including the planting of disease-resistant varieties and facilitating good soil drainage, are the best way to control strawberry disease. Do not thin or work among plants when they are wet.
Blossom blight or botrytis fruit rot shows up in discolored blossoms, wilted fruiting stems, and dark, wet spots on fruit. It can be controlled with sulfur or copper sprays if caught early. Otherwise, plants should be carefully removed and destroyed to avoid spreading the fungus.
Plants showing powdery mildew should be removed and destroyed as soon as it is spotted. Take care to wash and disinfect your hands and tools after dealing with infected plants to prevent its spread.
Verticillium wilt, seen in wilted leaves, dark runners and stalks, and inhibited growth can be treated with repeated applications of sulfur fungicides. If the disease continues to spread after treatment, remove and destroy the plants.
Seed Saving Instructions
Most June-bearing strawberries have been hybridized. Any seed saved from them will not breed true, but seeds from various types of non-hybridized, neutral or alpine berries can be saved.
Allow fruits to fully ripen on the vine before picking then gently mash them in a bowl with water. Let the mash settle and skim away any non-viable seeds that float to the top of the surface. Rinse repeatedly and strain the pulp, leaving only the seeds. Allow to dry thoroughly.
You may also try letting the picked fruit dry completely and then rub out the seeds from the berry’s skin with your thumb and forefinger.
Whole, well-ripened alpine berries can also be planted immediately in pots after picking, allowing the seeds to germinate. Start these plants indoors under lights after thinning until it’s time to transplant them into the garden.