Greetings crop pickers, here's the run down of the current top 12 polytunnel crops. Each of our 'Top of the Crops' have detailed growing guides, working with author and long-time polytunnel gardener, Andy McKee, we have produced a series of guides complete with all the do's and don'ts of growing the most popular crops. Whether you are looking to try growing something new, or just want to improve your existing crops these guides will make sure your polytunnel gardening is a big hit with all the family...
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If, like me, you're one of those people who can't wait for the first strawberries of the year, you can use your polytunnel to get these delicious morsels three weeks earlier than anyone else. This is best done by using an early variety and planting it the previous summer, to give the root system time to develop.
Varieties: Honeoye, a vigorous and productive early variety with some botrytis resistance - vital in humid weather.
Dig plenty of compost into the strawberry bed in early summer, and keep it absolutely free of weeds until the strawberries are planted. Suppliers send young plants by post any time from September to March: make sure you ask for the earliest delivery slot you can get (which usually means ordering by telephone). Plants that have time to establish themselves before growth stops for the winter will bear fruit earlier, and more heavily, than spring-planted ones.
When the plants arrive, soak them in water for half an hour and then plant them so that the crown of the plant is just level with the surrounding soil, and water them in well. Keep them well watered (but never waterlogged) until they show fresh new growth from the crown. Once this happens they will need less water until the fruit starts to form (usually in late March), and won't need feeding at all in their first year because the bed was composted heavily.
As soon as the fruit begins to form, put straw beneath the plants to keep the berries up off the ground and to suppress weed growth. Tunnel-grown plants produce lots of runners (strong, self-rooting stems) and these need to be removed throughout the growing season to stop the bed from becoming crowded (which promotes fungal diseases).
If you want to keep the plants for a second year (or
even a third) then remove the straw once fruiting
has finished, cut the plants down to 5cm high, and
then proceed as normal. The only difference to
first-year plants is that you will need
to feed them with a general purpose organic fertiliser
in the early spring, and again with tomato feed when
the first flowers appear. Don't keep the plants for
more than three years.
Diseases and pests: Slugs are best dealt with on a tunnel-wide basis by controlling habitat and removing them by hand on humid evenings when they are most active; if things get out of hand and you want to use pellets, only use organic ones which are based on ferrous phosphate and will not harm the soil. Moulds are a constant companion of the strawberry bed, especially in damp, cloudy conditions. They're best prevented by making sure that the bed never gets crowded and maintaining good ventilation, particularly in humid weather. Once mould arrives the spores spread quickly, so you need to check the berries on a daily basis and remove any affected fruit and dead or dying foliage.
Harvest: If your tunnel is visited by birds (and most are) you will need to protect the fruit by covering it with lightweight plastic netting, held off the plants with wire hoops or short lengths of bamboo. Make sure you choose a wide netting size (19mm or more) to let the bees pollinate the strawberry flowers. When you pick the strawberries, pick the calyx (the green leafy bit at the top of the berry) too, and don't heap the fruit up in a tiny punnet. This will give you perfect, undamaged fruit that will keep well for a few days – provided it makes it to the kitchen!
Recipe: There are so many ways to enjoy this fruit from cheesecake and crumble to salads and smoothies. The hardest part is saving enough whilst picking to actually make something in the kitchen.