What to do with strawberry plants in spring

Strawberries are incredibly easy to grow, with sweet, juicy fruits that are hard to resist. If you plant several varieties, you can have harvests from early summer through into autumn. They take up little space, so are great in containers and even hanging baskets.

• Begin harvesting perpetual strawberries
• Continue to water
• Remove straw mulch and netting after harvest
• Weed as necessary

Most strawberries are grown from runners or young plants, but alpine strawberries can also be grown from seed:

• Sow either in autumn or spring, into small pots or trays filled with John Innes No.1 or multi-purpose compost. Ensure the compost is fine and firmed prior to sowing

• Scatter the seeds thinly and evenly over the surface and lightly cover with sharp sand

• Cover the pot or tray with a clear plastic bag or sheet of glass to maintain humidity and shade until germination. Autumn-sown seeds should be overwintered in a coldframe

• Germination requires temperatures of 18–21°C (65–70°F), and can be slow and erratic

• As soon as the seedlings have two true leaves and are big enough to handle, prick them out 2.5cm (1in) apart

• Plant out in May, into a sunny or lightly shaded spot, in the ground or in containers

Water new plants frequently while they are establishing, and water all plants during dry periods through the growing season. Try to avoid wetting the crown or fruit, as this can promote fungal diseases.

In early spring, feed plants growing in the ground with a high potassium general fertiliser, such as Vitax Q4. Scatter half a handful per square metre/yard around the plants.

Feed those in containers and grow bags with a high potassium liquid feed, such as tomato feed, weekly or fortnightly throughout the growing season.

Weeding

Keep strawberry beds weed free. To reduce the need for weeding, you can plant through slits in weed-suppressing membrane or polythene sheeting.

Growing in containers

Strawberries are easy to grow in containers. Peat-free multi-purpose compost is a good choice. Suitable containers include grow bags, hanging baskets, troughs and tubs. Although traditional strawberry pots look attractive, they make it difficult to maintain healthy, productive plants.

Growing in pots avoids the build-up of soil problems, but vine weevil control is often essential.

Protecting flowers and fruits

If frost threatens, protect flowers and/or early fruits overnight with horticultural fleece.

Unless growing through polythene sheeting, protect the developing fruits from wet soil by tucking straw or ‘strawberry mats’ under the fruits as they begin to swell. This also helps to keep fruit clean and suppress weeds. Some gardeners prefer to use barley straw as it is soft, but wheat straw is fine to use too.

Netting will be needed to prevent birds stripping the fruit, but remove after harvesting to allow birds to feed on any remaining pests. Use 2cm (¾in) or 2.5cm (1in) plastic or other synthetic netting, and support the nets on a system of posts and wire or polypropylene string, making the cage 1.2m (4ft) high to allow access for picking.

If squirrels are a problem, protect fruit with wire mesh.

After harvesting

• Plant spare runners (young plants that develop as offshoots from the parent) into any gaps in the row or use them to replace old plants. Remove any unwanted runners

• Some gardeners prefer a continuous row in the second and third year, rather than spaced plants. The overall crop may be higher, but the quality of fruits is not as good Whichever method you use, keep a clear gap between the rows to give you access for weeding and harvesting

• With summer-fruiting strawberries, once cropping has finished, cut off the old leaves about 10cm (4in) above the crown to allow fresh leaves to develop. This isn’t necessary with autumn-fruiting plants – instead just remove the old leaves during the end-of-season clear-up 

• Also remove the straw mulch, fibre mat or black polythene sheeting, to prevent a build-up of pests and diseases

• Take off netting so birds can feed on any pests

Replanting

A bed of strawberries usually lasts up to four years if planted into well-drained, fertile soil that is free from troublesome weeds. To avoid disease build-up, choose a different plot and replant strawberries every three years.

Propagating

Strawberries can be propagated from runners (young plants that develop as offshoots from the parent) in late summer, but no later than early autumn:

• Sink 9cm (3½in) pots, filled with multi-purpose potting compost, beside your strawberry plants and insert individual runners into them

• Peg them down with U-shaped pieces of thin wire, about 15cm (6in) in length

• Keep well-watered to promote root growth

• Sever the new young plants from the parent plant when rooted

Perpetual strawberries produce few runners and new plants are best bought annually.

Seed-raised cultivars are available, but are not recommended, except for alpine strawberries (see Sow, above).

Growing in a heated greenhouse

Strawberries grown in a heated greenhouse can produce fruit as early as mid-March, although for high quality, well-coloured fruit it is better to aim for harvest in April.

Suitable cultivars for forcing under glass include ‘Cambridge Favourite’ AGM, ‘Honeoye’ AGM, ‘Rosie’, ‘Royal Sovereign' and ‘Tamella’.

For mid-March harvesting

• Bring container plants into the greenhouse in mid-December, but give no heat or water until the first new leaves appear, except for spraying with a fine mist of water on sunny days. Keep the atmosphere moist and restrict ventilation to sunny days. Increase watering as the foliage develops

• At the end of December, start to give gentle heat and keep the night temperature at 7–10°C (45-50°F). Too much heat will result in foliage at the expense of flowers

• In February, when the flowers open, raise the temperature to 15°C (60°F) and give ventilation during the day, although generally maintaining a moist atmosphere except at pollination time. Hand-pollinate daily with a soft paintbrush to ensure a good crop of well-shaped fruits

• When the fruit starts to form, increase the temperature to 18°C (65°F). For the highest quality fruit, thin the flowers by removing the smallest ones straight after the petals have fallen, leaving eight to ten fruits to mature

• Reduce ventilation and keep the atmosphere thoroughly moist at all times until ripening begins. Water copiously and spray with water frequently in sunny weather to promote large fruits and discourage mildew. As the fruit colours, increase ventilation, reduce watering and stop spraying with water altogether to reduce the risk of fruit rot

• Apply a half-strength liquid feed every 10 to 14 days until the fruit begins to colour. Too much feeding will result in soft, tasteless fruit and increase the risk of rotting 

For mid-April harvesting 

• Bring containers into the greenhouse in early January

• Start gentle heat about three weeks later, maintaining a night temperature of 4–8°C (40–45°F) until flowers begin to appear in February, then raise it to 10°C (50°F)

• Hand-pollinate as described above and follow the same watering and feeding regimes

• After petal fall, increase the temperature to 13°C (55°F). Once ripening begins, a lower temperature will improve colour and flavour but slow down the ripening process

For late April to early May harvesting

• Bring plants into an unheated greenhouse in February, and follow the steps for mid-April harvesting

There are three kinds of strawberries:

• Summer-fruiting strawberries â€“ these produce the largest fruit. They have a short but heavy cropping period over two or three weeks. There are early-, mid- and late-fruiting cultivars, cropping from early to mid-summer

• Perpetual strawberries â€“ sometimes called everbearers, they produce small flushes of fruit over a long period, from early summer until the first autumn frosts. The crops are not as heavy as summer-fruiting varieties, the fruits are smaller and plants are less likely to produce runners. Fruit size and overall crop reduces in the second year, so they’re best replanted annually

• Alpine strawberries â€“ these small shade-loving plants produce small, sweetly flavoured, aromatic fruits and tolerate cooler conditions than most larger-fruited strawberries. They need no special care and can be left to fend for themselves after planting

Always buy plants from a reputable supplier, so that cultivars are true to type and plants are disease free. 

Strawberries can be bought as potted plants or bare-rooted runners:

• Young plants in pots or packs of plug plants are normally on sale from late spring onwards and can be planted as soon as you buy them

• Runners look like little clumps of roots with very few leaves. Don’t be alarmed, this is how they should look. You can buy runners from late summer to early spring, and they should be planted in early autumn or early spring (avoid planting in winter when the ground is wet and cold)

• Cold-stored runners can be planted from late spring to early summer – these specially prepared runners will fruit 60 days after planting

• Alpine strawberries can also be bought as seeds – see Sow for details

There are lots of strawberry varieties to choose from, with various attributes, including different levels of sweetness, flavours, fruit size/shape and harvest times. If you plant several varieties with different cropping times, you can have harvests from early summer through to the first frosts. Look in particular for varieties with an RHS Award of Garden Merit (AGM), which shows they performed well in trials. See our list of AGM fruit and veg.   

Where to plant

Strawberries like fertile, well-drained, slightly acidic soil, and do best in full sun, but will tolerate some shade. Alpine strawberries thrive in shade. Avoid planting in sites prone to frost, which can damage the flowers, or in exposed locations, which make it hard for pollinating insects to reach the flowers. 

Strawberries are traditionally grown in rows in a dedicated bed or strawberry patch. In poor soil, it’s best to grow them in raised beds, which provide better drainage and increased rooting depth.

Avoid planting into ground that has previously been used for potatoes, chrysanthemums or tomatoes, because they’re all prone to the disease verticillium wilt. Strawberries also grow well in containers, including hanging baskets and windowboxes, as well as in grow bags.

Early crops can be produced by growing strawberries in a heated greenhouse – see Grow, below, for details.

How to plant

Prepare your ground by digging in two buckets of well-rotted manure or garden compost per square metre/yard. Add a general purpose fertiliser such as Growmore at 100g (3oz) per square metre/yard

Dig a hole large enough to accommodate the roots. Trim the roots lightly to 10cm (4in) if necessary, then spread them out in the hole. Ensure that the base of the crown rests lightly on the surface before firming in gently. Planting at the correct depth is important – if the crown is planted too deeply it will rot, if it’s planted too shallowly the plants will dry out and die. Water the plants in well.

Space plants 35–40cm (14–16in) apart, in rows 75–100cm (30in–3ft) apart.

Many gardeners grow strawberries through polythene sheeting, ideally white with black on the underside, but any plastic mulching film will do. This suppresses weeds, holds water in the soil and stops soil splashing onto the fruit. An irrigation system, such as a leaky pipe, installed under the sheeting also helps to maintain moisture.

When planting in autumn or early spring, remove the first flush of flowers on perpetual strawberries, but with summer-fruiting strawberries only remove the flowers if the plants are weak.

When you plant cold-stored runners in late spring to early summer, leave the flowers on. These will produce strawberries in 60 days, reverting to their natural cropping period the following year.

Strawberries ripen from early summer to early autumn, depending on the variety. 

Pick when they’re bright red all over, ideally during the warmest part of the day, as this is when they’re at their most tasty.

Eat them as soon as possible – they don’t keep well once ripe. Most don’t hold their shape when frozen.

Recommended Varieties

Strawberries can suffer from a range of problems, from bird and slug damage to specific problems such as strawberry virus and strawberry black eye. Fruits may occasionally be affected by phyllody. The fruit fly spotted wing drosophila (SWD) is likely to become an increasing problem.

They may also suffer cold damage.

Container-grown strawberries can be damaged by vine weevil.

For strawberries grown under glass, aphids and red spider mite are the most troublesome pests, while mildew and grey mould might also be a problem.

Grey mould

A usually grey, fuzzy fungal growth which can begin as pale or discoloured patches. Grey mould ( botrytis) is a common disease especially in damp or humid conditions. Spores enter plants via damaged tissue, wounds or open flowers. Mould can also damage ripening fruit such as strawberries. Black resting spores survive over winter.

Remedy

Remove damaged plant parts before they can become infected. Cut out infected areas into healthy tissue and clear up infected debris. In greenhouses, reduce humidity by ventilating and avoid overcrowding of young plants and seedlings.

Powdery Mildew

Appears as a white powdery deposit over the leaf surface and leaves become stunted and shrivel.

Remedy

Keep the soil moist and grow in cooler locations.

Frost damage

Late frosts can damage growth, leading to it dying or being distorted.

Remedy

Remove any damaged growth and protect the bed with a double layer of horticultural fleece if frost is forecast.

Vine weevil

Adult vine weevils eat notches in the edges of leaves, while plump, creamy white larvae with brown heads cause more damage to the roots, on which they feed. This can kill the plants.

Remedy

Apply biological control.

Nigel Slater’s soft set strawberry jam is easy to make and tastes of summer.

This strawberry and mascarpone tart is simple to make but looks impressive.

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