Strawberry

Garden strawberries (Fragaria × ananassa) are low-growing perennials in the rose family, grown for their sweet red fruit. The plants grow 6 to 12 inches (15–30 cm) high and 1 to 2 feet (30–61 cm) wide. Gardening experts describe three main types: summer-fruiting strawberries, with one short, heavy crop; perpetual (everbearing) strawberries, which fruit in smaller flushes from early summer to early autumn; and alpine strawberries (Fragaria vesca), with small, aromatic berries. In the US, June-bearing varieties, which fruit in May and June, are the most common, and day-neutral varieties flower over a longer season.

Seeds or plants? Most strawberries are grown from plants, not seed. Summer-fruiting and perpetual strawberries are grown from runners or young plants, while alpine strawberries can also be grown from seed. Some day-neutral hybrid garden strawberries are sold as seed too, but growing strawberries from seed takes patience.

Starting with plants (the usual way). Plant in spring, late summer or early autumn. Planting in August or September gives plants time to settle in before they fruit the following year. In Maryland, bare-root starter plants go out in March or early April, as the soil begins to warm. Planting depth matters: if the crown is buried too deep it rots, and if it sits too high the plant dries out quickly. Gardening experts space plants 35–40 cm (14–16 in) apart in rows about 75 cm (30 in) apart.

Starting from seed. Expect a slow start. The seeds first need about a month in the refrigerator (stratification) to break dormancy. Then they can be germinated and grown indoors for 6–8 weeks before going into the garden. Gardening experts sow thinly, pressing the seeds into a moist soilless mix, keeps the soil at 60–75 °F (16–24 °C) if possible, and notes that seedlings can take 2–3 weeks to emerge. For alpine strawberries, gardening experts sow in spring or autumn and lightly covers the seeds with sharp sand. They germinate at about 18 °C (64 °F), though germination can be slow and patchy, and the plants often fruit in their first year.

Site and soil. Strawberries grow best, and produce their sweetest fruit, in a sheltered spot in full sun, though they tolerate some shade. They like fertile, well-drained, slightly acidic soil; gardening experts recommend a sandy loam with a pH between 6.0 and 6.5. If your soil drains slowly, build a raised bed at least 12 inches (30 cm) high. Avoid spots prone to late frosts, which can damage the flowers.

Pots and baskets. Strawberries grow well in pots, growing bags, hanging baskets, troughs and tubs. Plant with the crown level with the compost surface, about 20 cm (8 in) apart, put the container in a sheltered, sunny spot, and water regularly. Containers also keep soil diseases from building up, and the fruit is less likely to be eaten by slugs.

Watering. Strawberries have short roots, so they need frequent watering: about 1 to 1½ inches (2.5–4 cm) of water a week during key growth stages. Water new plants regularly while they settle in. Try not to wet the crown or the fruit, and water in the morning so any splashes dry quickly; this helps prevent gray mold.

Mulching. Straw under the plants as the fruits form keeps the berries clean and dry. Gardening experts suggest a 1- to 2-inch (2.5–5 cm) layer of straw and warns against grass clippings, which can smother plants and promote disease. Shallow roots also let winter freezing and thawing push plants out of the soil, so mulch them with straw or shredded leaves in late fall, when nights approach 20 °F (−7 °C).

Flowers and runners. For June-bearing varieties, remove the flowers for the whole first season so the plants build strong roots. Runners root easily: remove them for better fruiting, or use them to increase your plants.

Feeding. Plants in decent, regularly mulched soil rarely need extra feeding. In containers, feed every two weeks during the growing season, switching to a high-potassium liquid feed when the first flower buds form.

Renewing. Plants generally need replacing every 3 to 4 years. Replant to avoid disease build-up, and make the new bed in a different spot.

Common diseases include gray mold (Botrytis), anthracnose and leaf spot; in South Carolina, Botrytis fruit rot is the most common fruit disease. Disease can arrive on plants from friends or nurseries, so buy certified disease-free plants from a reputable source. Insect pests include tarnished plant bugs, sap beetles, leafhoppers and spotted-wing drosophila, and slugs, birds, squirrels and other wildlife eat the fruit. Bird netting is the most effective way to cut losses to birds. In containers, vine weevils can be a problem.

Strawberry plants are hardy, but if frost is forecast while they’re flowering or carrying young fruit, cover them overnight.

Fruits start ripening about 5 weeks after the plants bloom, and the harvest usually lasts about 3 weeks, depending on spring weather. Berries don’t all ripen at once, so pick only those that are fully red. Berries picked before they’re fully red keep changing color but won’t get any sweeter. Harvest every other day or three times a week, ideally early in the morning while the fruit is still cool.

Wash strawberries just before eating, not before storing them. They keep in the refrigerator for 3 to 5 days.

Pet poison experts list strawberries (Fragaria species) as non-toxic to dogs and cats.