How to grow Strawberry in New Zealand

Where to plant

Choose a sunny, sheltered spot: without full sun the berries have little flavour. Strawberries like rich, warm, free-draining soil. Dig in compost and sheep pellets, then plant on mounds about 10 cm high, which improve drainage and air flow around the plants. On heavy or clay soil, mounds or raised beds are essential.

Do not plant where strawberries, tomatoes or potatoes grew recently, and start each new bed with clean plants rather than old, tired runners.

• Northland, Auckland, Waikato and the Bay of Plenty: plant from April to July. Plants set in the cool of winter establish well and give a bigger crop.
• Wellington and Nelson: plant in late autumn or winter while plants are in garden centres, and no later than early spring.
• Canterbury: plant in April or May, or in August and September as soon as the soil can be worked. Skip midwinter, when plants sit in cold, wet ground.
• Otago and Southland: plant in April so the crowns root in before winter, or wait until September and October.
• Central Otago: plant in spring, as autumn-planted crowns can be lifted out of the frozen ground over winter.

Choosing a variety

Strawberry varieties are grouped by how day length affects their flowering. Planting a mix spreads the harvest across the season.

• Short-day types such as Camarosa, Chandler, Pajaro and Ventana form flower buds in the short days of winter, giving a light early crop and then a heavy summer crop. Plant them in mid winter. Camarosa tolerates cooler, moist conditions and suits southern gardens.
• Day-neutral types such as Albion, San Andreas, Aromas and Monterey flower and fruit from spring through summer into early autumn, and can be planted later than short-day types.
• Camino Real is a heavy cropper of dark red, sweet berries that fruit later in the season.

How to plant

1. Dig in compost and sheep pellets, then work a strawberry mix or fertiliser into the soil.
2. Make mounds or ridges about 10 cm high. Running rows north to south gives even sun and ripening.
3. Soak the plants in a seaweed tonic before planting to reduce transplant shock.
4. Plant about 15 cm apart with the crown, where the leaves meet the roots, sitting just above the soil. A buried crown rots.
5. Water in well, then mulch with strawberry straw or pea straw to keep the roots moist, the fruit clean and the weeds down.

Watering and feeding

Keep the soil evenly moist but not soggy, especially in dry spells and in containers. Overwatering gives watery, tasteless fruit and encourages grey mould in humid weather. Water at the base, not over the leaves and fruit.

If you planted into a strawberry mix, extra feeding is only needed from mid spring. Feed with a strawberry fertiliser in October and November, or every four weeks through spring and summer. Too much fertiliser gives leaves at the expense of berries.

Pruning and care through the year

• Net the plants once they start flowering, as birds take ripe berries.
• Keep the bed weed free, as strawberries dislike competition.
• Pinch off runners during the season so the plants put their energy into fruit, or let a few root into pots to make next season's plants.
• After fruiting, tidy old leaves and remove the runners you do not need.
• Replace plants every two to three years. Older plants crop less and are more prone to viruses.

Harvesting

Pick when the berries are fully red, glossy and fragrant, as they do not ripen further once picked. Pick in the cool of the morning, snipping or pinching through the stalk just above the green cap. During the peak of the season check every day, as berries ripen fast in warm weather, and the more you pick the more the plants produce.

Strawberries are best eaten fresh. To freeze them, hull and spread them on a tray to freeze individually, then bag them.

Growing in pots

Strawberries grow well in pots, troughs, hanging baskets and even a bag of strawberry mix laid flat with drainage holes punched underneath; five or six plants fit in one bag. Use a strawberry or potting mix, mulch the top, place in a warm, sunny spot, and water often, as containers dry out quickly. Refresh the mix each season.

New plants from runners

Strawberries send out runners with baby plants along them. Peg a few healthy ones into small pots of mix, cut them free once rooted, and plant them out for next season. Take runners only from vigorous, healthy plants, and in the north get them planted by August so they establish before fruiting.