Tomatoes, cucumbers and chillies are often the first crops people think of when they imagine a polytunnel. But after asking growers in a popular polytunnel Facebook community:
“What’s the one thing you’ve grown in your polytunnel that surprised you the most?”
The answers revealed just how versatile a polytunnel can be.
From tropical fruits and Mediterranean crops to giant vegetables and even peanuts, UK growers are pushing the boundaries of what can be grown under cover.
Here are some of the community’s most surprising successes.
Photo by Viviane Souza Mathias
1. Melons and Watermelons
One answer dominated the discussion: melons.
Growers reported success with:
- Honeydew melons
- Pepino melons
- Crimson Sweet watermelons
- Baby watermelons
Several growers even harvested football-sized watermelons and successfully saved seed for future crops. Others were surprised at just how productive melon plants could be in a UK polytunnel.
Why they thrive: Melons love heat, shelter and consistent moisture; conditions a polytunnel provides perfectly.
2. Tropical Crops in North Wales? Apparently Yes.
One grower reported successfully growing:
- Lemons
- Ginger
- Turmeric
…all in North Wales.
Other growers mentioned:
- Galangal
- Shampoo ginger
- Blood oranges
- Pomegranates
A polytunnel can create a microclimate several degrees warmer than outside, opening the door to crops many gardeners would never consider.
3. Peanuts in the UK
Perhaps the biggest surprise of all?
Peanuts. One grower simply replied:
“Peanuts 😁”
While rarely grown in Britain, peanuts need a long, warm growing season, making a polytunnel one of the few places where they’re worth trying.
How to Grow a Peanut Plant | BBC Gardeners World Magazine
4. Winter Harvests That Just Keep Going
Many growers weren’t surprised by what they grew, but when they were able to harvest.
Examples included:
- Carrots harvested in December and still cropping in May.
- Tomatoes harvested into November and even December.
- Cauliflower and broccoli harvested in March when little else was available.
- Overwintering onions ready before summer crops are planted.
For many growers, extending the season is one of the biggest benefits of owning a polytunnel.
5. Giant Vegetables
Several growers reported crops reaching extraordinary sizes.
Highlights included:
- Birdhouse gourds that became enormous.
- Swiss chard growing to around three feet tall and winning first prize at a local show.
- Brussels sprouts growing twice as tall as outdoor crops.
Sometimes it’s not the crop itself that surprises growers – it’s the sheer scale.
6. Crops Growers Wish They’d Tried Sooner
The conversation also highlighted crops that exceeded expectations:
- Pak choi
- Thai basil
- Edamame
- Cucamelons
- Loofah
- Strawberries
Many of these are rarely seen in a typical vegetable patch but perform exceptionally well under cover.
Perhaps not a great surprise, but cats featured a lot in the warmth of a polytunnel
Honourable Mentions
Not every surprise was entirely welcome.
Growers also reported unexpectedly cultivating:
- Weeds
- Nettles
- Mice
- Cats (apparently polytunnels make excellent cat lounges)
Final Thoughts
If this discussion proves anything, it’s that a polytunnel isn’t just a place for tomatoes.
With a little experimentation, UK growers are successfully producing everything from tropical fruit and peanuts to giant gourds and winter harvests that last well into spring.
The only question is:
What’s the most surprising thing you’ve ever grown in your polytunnel?
