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Strawberry Yields

The old guard will tell you this mouth-watering crop is best left to professional growers. Stephen Shirley debunks the myths with his failsafe guide to succulent summer

Did you know the commonest supermarket strawberry, ‘Elsanta’ is known to insiders as ‘the fruit that bounces’? While durability and shelf life are something to shout about if you’re airfreighting food halfway around the globe, it doesn’t count for much if you want strawberries that make an impact on your taste buds.

Growing your own is the best way to sidestep rubbery, flavourless fruit, but would-be growers are often put off by the stigmas of a short cropping season and the need for vast swathes of space. Neither of these fears hold water – in fact strawberries are one of the most accommodating fruits of all. Although conventionally grown in beds, they will do just as well in pots and tubs, window boxes and even hanging baskets. And unlike most fruits they’re self-fertile so you don’t have to rely on pollination from another plant to get cropping.

Types Of Strawberries

Strawbs can be broken down into three types: summer fruiting, perpetual (also known as ever-bearing or remontant) and the often-overlooked alpine or woodland strawberry. Summer fruiting varieties yield a large crop in late spring or early summer and may provide a few extra berries throughout the season. Perpetual types produce a good sized crop in the spring and continue to yield berries regularly up until the first frosts. Alpine strawbs crop in a similar pattern to perpetuals, but the fruit is much smaller in size. Most summer varieties produce leaves and fruit on ‘runners’ (long trails of growth that spread out over the surface of the soil) while alpine and perpetual varieties grow in clumps.

All strawberries prefer a humus-rich, moisture-retentive soil which should ideally be slightly acidic (pH 6.5–6.8) and sheltered from wind; they have a shared hatred of waterlogged soil too. An open sunny site will produce the highest yields but a spot of shade won’t be too harmful, particularly for woodland varieties.

Planting Them

The traditional planting times are early spring or mid to late summer, although you can get cracking at any time of year (except the middle of winter). A strawberry bed will be active for at least three years and possibly up to five, so make sure you choose a site you’re willing to commit to the crop. If you’re lucky enough to own a fruit cage, don’t waste precious space in it with strawbs – they are easy to protect with netting or fleeces when required and you can allow bug-munching birds access to the plants when they aren’t cropping. Summer and perpetual varieties should be planted 45cm (18in) apart in rows 75cm (2½ft) apart; alpine varieties can be kept a little closer at 30cm (1ft) in rows 60cm (2ft) apart.

Matted Rows

Dedicated growers can increase their yield by up to 50 percent by using ‘matted rows’. Choose a variety that produces runners (such as ‘Rambing Cascade') and peg them down – but don’t cut them off from the parent plant. This produces a solid area of growth spreading about 20cm (8in) either side of the row (runners that grow beyond this point can be cut off). The increased plant coverage also helps keep weeds at bay.

GYO Tips: Successful Strawberries

Unless the plants are particularly strong, crops planted in late spring should be de-blossomed (have their flowers removed) to stop them fruiting in their first year. This might sound drastic but it will substantially swell your yield in subsequent years.
Protecting your crop with cloches is the easiest way to extend your cropping season and increase yields. If you can, divide your crop into three – put a cloche over one third in February, cover another third from April onwards and leave the final plants open to the elements. Rotate your system each year so that all the plants get a full season outside. Make sure covered crops get enough ventilation and provide shade on very sunny days to avoid scorched leaves.

A lighter soil will produce earlier crops, so if you want to spread your season without cloches split your bed in two and work in more organic matter on one side than the other.

Hand pollination may be necessary in very cold spring weather, when insects are scarce. Simply dab the centre of each flower with a soft paint brush every couple of days. This will disturb and transfer the pollen from the anther to the stigma in the same way that insects naturally would.

Pot-grown strawberries that have been left in a cool greenhouse all winter should be placed outside, as they only flower after exposure to the cold. However, outdoor strawberries (already exposed to the elements) should be brought into the greenhouse to encourage them to fruit.

If you’re using hanging baskets, choose a variety with long runners such as ‘Rambling Cascade’. A good rule of thumb is to grow one plant per 5cm (2in) pot, so a 20cm (8in) container will hold up to four plants. Dedicated strawberry pots have planting pockets at different levels, which makes things more straight-forward – just grow one plant per hole and two or three on top.

Caring For Them

Strawberries don’t need much looking after as long as they are watered well after planting and in dry spells – and you avoid watering ripening berries. As the fruit starts to swell, cover the ground underneath with straw to keep the fruit clean and away from damp soil. After cropping, cut off the old leaves and any runners that you don’t need about 7.5cm (3in) above the crowns.

Once you’ve got a few of them up and running, propagating strawberry plants is a doddle. If you’ve got varieties that produce runners, such as ‘Rambling Cascade, simply peg them into the soil in June or July or, better still into small pots of compost. Leave them for four to six weeks to take root and form a separate plant – then you can cut them free from the mother plant and move them to their final growing position. Varieties that don’t produce runners (try ‘Flamenco’) are propagated by dividing – lift a mature plant and cut it into two or three smaller clumps with at least three shoots each.

I only know of a handful of growers who propagate strawberries from seed, strange given that they are the only fruit that bare their seed on the outside (what better reminder?). Propagating from seed is easy, almost always successful and if you don’t have access to existing plants, by far the cheapest way to establish a strawberry bed. Alpine varieties are best sown in the autumn and grown on under cover before planting out in early spring. Perpetual varieties are best sown in late February or early March and should be fruiting in as little as six months.

Beating Pests

Insect pests such as vine weevils (or more specifically its grubs) can decimate a strawberry bed in no time and allowing wild birds access to the plants when they aren’t cropping is essential. You should also treat the bed with nematodes (microscopic worms that hunt down and kill pests – try The Organic Gardening Catalogue, 0845 130 1304) in April or May and again in mid-autumn.

Any soft fruit grower should be armed to the teeth with birdproof netting and slug deterrents (to avoid the slimy scourge altogether, keep your strawbs safe in hanging baskets). There’s a slew of other pests and diseases such as blossom weevil, strawberry seed beetle, mildew and crown rot that can damage your crop, but spraying regularly with an organic bio-stimulant (such as BioFriend Plant Defence) will keep them at bay and improve the health of the plants. They also contain a high proportion of garlic, which won’t taint the fruit but is a natural fungicide.

OVER TO YOU

There are hoards of dedicated GYOers cramming our online forum with hints, tips and tricks every day – and this is what they had to say about strawberries. If you fancy seeing your name printed in Grow Your Own and catching up on the latest discoveries in the world of fruit and veg, log on to www.growfruitandveg.co.uk/grapevine

Pigletwillie says:
“I use a four year rotation plan for my strawbs. In the first year the plants establish themselves and will crop very lightly – so don’t take runners from them.The second and third year plants are your main croppers and it’s best to remove any runners so they conserve energy for the following year’s fruit. The fourth year plants are on the wane – as they’re destined for the compost bin these are the ones to take propagating runners from.”

Mrs Dobby says:“When I first took over my allotment the strawberry bed was completely overgrown, so I moved the plants to another area that had been dug over thoroughly.As each individual plant was lifted I carefully removed the old leaves and runners, then replanted the bare crowns into prepared beds covered with weed control fabric.The idea isn’t just to keep weeds at bay, but also to deter slugs.”

STRAWBERRIES:WHAT TO DO THIS MONTH

February is a great month to make a start with strawbs. Prepare your bed by digging it over, removing any weeds and adding a small amount of manure (make sure it is well rotted to avoid burning the roots as they form). They can be planted out immediately but be prepared to protect them with cloches or fleece if the weather turns.

Hanging baskets and tubs can be planted up and started under glass for cropping this year (so don’t remove the flowers). You can also pot up the plants ready to transplant into window boxes – just make sure you don’t move them out until the threat of frosts has passed (mid May).

STRAWBERRIES FOR BEGINNERS

• Alpine varieties are best for learner growers – there are no runners to worry about and they are just as happy dotted about your flower borders or grown in pots. They are also easy to propagate from seed.
• Summer-fruiting ‘Alice’ produces a uniformed sized crop of sweet fruit and boasts excellent disease resistance.
• The reliable perpetual variety ‘Aromel’ produces a good crop of flavoursome medium-sized berries.
• ‘Senga Sengana’ is an excellent choice for window boxes and hanging baskets as it produces runners up to 1.5m (5ft) in length. It also does well in the open ground.
• ‘Sweet Temptation’ is an excellent variety for growing from seed and can start producing fruit within six months.

ESSENTIAL INFORMATION

Stephen Shirley is MD of Victoriana Nursery Gardens, which stocks a selection of topnotch strawberries including ‘Rambling Cascade’ (also known as ‘Senga Sengana’), alpine variety ‘Tumbleberry’ and recently-launched ‘Sweet Temptation’ seeds. The Kent-based GYO specialist also stocks organic plant stimulant, BioFriend Plant Defence. To find out more call 01233 740 529 or visit victoriananursery.co.uk

This article first appeared in the February 2007 edition of Grow Your Own magazine. To download a pdf copy of the original article click on the image below...

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