Q: I’m thinking of buying a polytunnel to extend the growing season, but while many of my gardening friends think it’s a great idea, others have warned me off it, saying that they’re a lot of work to look after. Any advice would be welcome. PK, Co Kildare
A: As someone who loves polytunnels in the way that others love designer clothes or exotic holidays abroad, it’s difficult to give you an entirely unbiased answer. I really do believe that these protected growing structures are worth their weight in gold, especially given Ireland’s cool, damp climate and the daunting prospect of increasingly extreme weather events resulting from climate change.
Polytunnels can extend the growing season in this country by as much as six weeks at either end, sheltering plants from the extremes of heavy rain, snow and cold wind so that they flower and crop far earlier, for much longer, and much more generously.
In summer-autumn, they allow Irish gardeners to successfully grow the kinds of heat-loving crops such as tomatoes, cucumbers, peppers, French beans and melons that would inevitably struggle outdoors. Even in the depths of an Irish winter, they can still be put to great productive use to grow a wide range of leafy crops including many kinds of salad leaves, chard and herbs.
Food crops aside, you can also use them to grow a wide range of beautiful cut-flowers from very early cropping sweet pea, ranunculus and anemones in spring to a late crop of dahlias or chrysanthemums.
I also know gardeners who use their polytunnels to create indoor ornamental gardens, and others who use them as a private chill-out spot that can be enjoyed even on cold but sunny winter days.
Yes, it’s true that they do require regular TLC in the form of careful ventilation to ensure that temperatures don’t climb too high on bright, sunny days, as well as careful irrigation to make sure that plants receive sufficient water. Never so much however, that it raises the risk of plant pests and diseases (before erecting any polytunnel, always make sure that you have a decent water supply nearby).
You’ll also need to give it a very thorough wash-down in early spring while, as a rule, most conventional polytunnels also need to be re-covered with a new, tight skin of plastic after about ten years (some last much longer).
It’s also fair to say that protecting them from winter storm damage can be a little bit of a bind. When the Beast from the East hit Ireland back in 2018, for example, many polytunnel owners had to get out and brush the very heavy blanket of snow off their tunnels to prevent them ripping or collapsing.
Even just an average autumn storm can cause damage if the doors and vents are left open rather than being firmly secured to make it as airtight as possible.
But, all in all, I think this is a small price to pay for the great rewards of polytunnel gardening.
Just make sure to source yours from a reputable supplier such as Colm Warren Polytunnels (thepolytunnelcompany.ie), and to get some good advice on choosing the very best site as well as preparing it in advance of installation.
If possible, also allow for the cost of installing a basic electricity source in the shape of a few waterproof sockets and a light suitable for outdoor use. The former will allow you to use an electric propagator or heated mat (invaluable for propagating really early crops), while the latter will enable you to continue to work comfortably on even the gloomiest winter evenings.
