GARDENING Growing in polytunnels

Tunnel Vision


Organic Growing
Hans Wieland

Do you love tomatoes, basil, sweetcorn and cucumbers? Would you like to be eating your first crop of new potaoes as early as June? Do you want lettuce throughout the winter? If the answer to those questions is yes then the only option in the West of Ireland is to invest in a polytunnel.
In 1985, when I arrived with my family in Ireland, there were only two polytunnels in the country – one in Ballydehob in Cork and the other one in Rossinver in Leitrim. Now you see them everywhere, and for very good reason: Polytunnels are an excellent way of increasing productivity at a low cost.
Polytunnels are great for growing tender vegetables, which require higher temperatures than normally exist in an Irish summer (tomatoes, peppers, aubergines, cucumbers, basil, sweetcorn); For extending the growing season, both in the spring and autumn (carrots, calabrese, celery, courgette, beetroot, scallions, radish and annual herbs like dill and coriander); for winter cropping – fresh salad leaves can be harvested all through the winter (winter purslane, mizuna, salad rocket, Tat soi, radicchio and lambs lettuce); and for plant propagation – polytunnels can successfully be used for raising plants either on heated benches or even in the soil for bare-root transplant raising.

Ideal crops
Climbing French Beans are an excellent polytunnel crop. Seeds can be started in small pots or sown in situ if the soil temperature is above 10ºc. Sowings can be made from March until early summer for cropping from late June until late Autumn. Seeds should be sown about 5cm and 15cm.
Cucumber also do well. One plant can produce enough cucumbers for a family over the summer.
Sow in April in seed trays with a temp of 24-25ºc, maintaining a 15ºc minimum. Pot on when leaves have expanded. Grow in a raised bed in single rows with 45cm spacing. Plant from early May on. Train up a string that is buried under the plant and supported by a crop wire overhead.
Tomatoes are possibly the most popular under cover crop. Sow early mid March with temp of 20-24ºc in seed trays. Pot on once plant has developed a second set of leaves. After germination maintain a minimum temperature of 15ºc. The beds must have a rich supply of organic matter in the form of well rotted farmyard manure or compost. Potassium is very important for tomatoes and may be supplied using seaweed meal or dust. Plant in double rows with 50cm between rows and 60cm between plants.
Other suitable crops include Basil, chili, sweet peppers, lettuces, sweetcorn and potatoes.

Warning: Don’t buy a small tunnel! The benefits will become obvious very quickly and you will become addicted. A good-size family tunnel is about 12 to 15 meters long.

Hans Wieland is joint manager of The Organic Centre, Rossinver, Co Leitrim, which offers courses, training and information in organic growing, and runs an Eco Shop and an online gardening store. For more information, visit www.theorganiccentre.ie, e-mail info@theorganiccentre.ie or phone 071 9854338. Questions or comments? Contact Hans at living@mayonews.ie.