One of the best things about having a polytunnel is that it can help you to grow and eat your own food all year round. This month, one of the jobs in your polytunnel is to choose and plant onion sets for overwintering. Growing onions from sets is far easier than growing onions from seed, and growing them inside your polytunnel makes the process even easier, as you are far less likely to have to contend with birds pulling the sets from the ground.
When you choose onion sets to plant in your polytunnel in September, it is important to think about which varieties are best planted at this time of year, as well as which varieties will do well in the soil and other conditions where you live. Some onions will do best when planted at this time of the year, while others are far better suited to planting in the spring. It is best to source your onion sets from as locally as possible, as such sets will be far more likely to be suitable for growing in your geographic location. Remember, the onions that grow well in the south of England will not necessarily be a good choice for Yorkshire, or the Scottish Highlands…
Which Onion Sets For Overwintering Are Available?
There are a range of different white and red onion varieties available to purchase in the UK that are suitable for overwintering in a polytunnel. Options include:
- ‘Hi Keeper’
- ‘Stuttgart Giant’
- ‘Red Baron’
- ‘Red Winter’
All of the above can be found for sale in a number of locations around the UK. Enquire at your local garden centre or plant nursery, or source your sets online from a reputable retailer in your area.
Make sure that you plant your onion sets in time so that they establish root systems before the really cold weather arrives. This is a job to get on with before the end of this month if you can find the time. Plant sets at a spacing of around 20-25cm and mulch with good quality home-made compost or leaf mould. Water sparingly over the winter and then begin weeding little and often I spring when green things begin to burst into life once more and you could be enjoying onions from your polytunnel and clearing the space out in time to plant your warm weather summer crops next year.
Do you plant onion sets for overwintering in your polytunnel? Which varieties do you choose? How successful have your efforts been? Let us know in the comments below.
Elizabeth Waddington is a writer and green living consultant living in Scotland. Permaculture and sustainability are at the heart of everything she does, from designing gardens and farms around the world, to inspiring and facilitating positive change for small companies and individuals.
She also works on her own property, where she grows fruit and vegetables, keeps chickens and is working on the eco-renovation of an old stone barn.