A polytunnel may not look as pretty as a greenhouse does, but for Michael Kelly it's not only a productive tool, it's a refuge from gales
OK, so our polytunnel is undeniably ugly, sitting in the corner of the garden like a recently-landed polythene spaceship, but it's the most productive food growing space in the entire garden (and possibly – whisper it – my favourite place in the whole world). The polytunnel is often considered to be a poor man's greenhouse but my polytunnel wears that tag defiantly, like a badge of pride rather than an insult.
Per square foot of growing space, polytunnels are cheap. The one I have in the garden is 15ft wide and 30ft long, and cost me around €600. A greenhouse of those dimensions would cost 10 times that. So think of your polytunnel as a reliable work-horse, and a greenhouse as a preening show pony. Of course, the show pony is pretty to look at, but when you're looking to get stuff done, call in the work-horse.
Basically a polytunnel is no more complex than a sheet of UV-treated polythene (clear plastic) stretched over semi-circular galvanised steel hoops. They come in all shapes and sizes, but are tall enough to walk into. The plastic is buried in the ground at the sides to anchor it, and a door is cut into the plastic at each end for ventilation.
I've had my polytunnel for about seven years now and its purchase was that rare thing for me – an incredibly shrewd investment. It has churned out thousands of euros worth of vegetables over those years.
A polytunnel has its own micro-climate. On a very warm sunny summer's day the temperature in the tunnel can reach up to 40 degrees. It also retains its heat longer in the evening. It's a place that is always dry, generally warm, often decidedly balmy and even sub-tropical. It may be a crappy Irish summer outside, but inside it's basically the Med. Vegetables that won't grow at all (or badly) outside in Ireland will do well in a polytunnel. So for example, crops that need warm weather like tomatoes, cucumbers, aubergines and peppers will thrive.
In addition, times of the year that are generally inhospitable to vegetable growing in Ireland can be made fruitful with the benefit of a tunnel. Though polytunnels are not immune to frost, it is very rare that the soil inside will freeze over. This has the benefit of extending the growing season at both ends, since late and early frosts are so detrimental to vegetables.
My first sowing in the tunnel happens in February. The last happens in November. That extends my sowing season by about two months at either end of the year.
In fact, with a little planning, the tunnel can be productive for 12 months of the year. Even though we are now in the depths of winter, there are still vegetables in the tunnel. I sowed oriental salad leaves such as mizuna, mibuna, tat soi and mustard in the tunnel in October and they fared well, giving us access to fresh salad leaves all winter. Last year we were able to eat cucumbers and tomatoes right up to mid-November.
Some of my happiest days in the garden have come courtesy of the tunnel. I get a particular kick from being able to work away while the rain beats down or a gale blows outside.
I love the deep concentration of smells inside – a blast of lemon verbena as you brush past it, or the smell of tomato plants hanging thick in the air.
Compared to the challenging environment of outdoor growing, the polytunnel feels somehow gentler, more forgiving and more controlled. Plants just seem to thrive – they are vigorous, lush, verdant. While courgette plants outside struggled to get going last year, in the tunnel they took off like rockets – trailing over the beds and paths to the extent that I had to cut them back. There are pests too of course, but not as many as outdoors.
The polytunnel is my cocoon – a little, plastic bubble of sanity in a world gone mad.
Michael Kelly is author of 'Trading Paces' and 'Tales from the Home Farm',
and founder of GIY.