Garden Dome vs Polytunnel: Which Do You Need?
Share
Quick answer
Choose a polytunnel if you want cheap, large-scale cover for growing crops; choose a garden dome if you want a comfortable, year-round room for people that suits plants too. A polytunnel gives a serious grower the most sheltered planting space for the money. A dome gives you a light-filled space to use and enjoy, with room for plants as well. They aren't really rivals; they answer different questions.
What each one is for
A polytunnel is a steel hoop frame covered in polythene sheeting. It's inexpensive, covers a large growing area, and is built for one thing: protecting crops. It's not weatherproof in the way a building is (the polythene tears, degrades in UV, flaps in wind and needs replacing every few years), and it's not somewhere you'd furnish and relax.
A dome is a solid polycarbonate structure built as a durable, attractive room, comfortable to spend time in year-round, that also happens to suit plants thanks to its abundant light. Its solid, UV-protected panels don't tear or flap, the material is around 250 times more impact resistant than glass, and once the dome is anchored, its geodesic shape spreads wind and snow loads across the whole frame. The roof vents, windows and sliding door let you manage airflow and heat, which matters to plants as much as to people. On an open, windy plot, choose the Ultra or Extreme specification.
Side by side
| Polytunnel | Garden dome | |
|---|---|---|
| Built for | Growing crops | A room for people (and plants) |
| Covering | Polythene sheet | Solid, UV-protected polycarbonate |
| Durability | Sheet degrades; typically replaced every few years | Solid panels that don't tear; anchored geodesic frame spreads wind and snow loads |
| Comfort as a room | None | High |
| Looks | Utilitarian | Striking feature |
| Cost | Low | From £899 |
| Best for | Allotment-scale growing | Relaxing and spending time in a light-filled space |
Which one do you need?
A polytunnel is the right buy if:
- growing is the whole point and you want the most covered planting space for your money
- you're happy to plant into beds in the ground and re-cover the frame every few years
- it can sit somewhere practical rather than on show
A garden dome is the right buy if:
- you want a room you'll actually use: the Mini seats 4-5, the Standard 6-8 and the Large 12-16
- plants are part of the picture rather than all of it: pots, staging and a chair or two in the light
- you want something that looks good in the garden and goes up quickly, with individually numbered panels bolted together in an afternoon or a day (or our Built for you installation service can build and anchor it for you)
Neither keeps a hard frost out on its own, so in a dome a small heater keeps tender plants safe and makes the space cosy for you on cold evenings. If you have the room, the two also work well side by side: a polytunnel for crops, and a dome near the house for sitting among your favourite plants.
If plants are part of the plan, our guide to the best garden dome for plants and growing goes deeper, and garden dome vs greenhouse compares the dome with the other classic growing structure.
Frequently asked questions
What's the difference between a dome and a polytunnel?
A polytunnel is cheap polythene cover for growing crops; a dome is a durable polycarbonate room for people that suits plants too. Different purposes entirely.
Can I grow plants in a garden dome?
Yes. The abundant light suits plants, the roof vents and windows help you manage heat and airflow, and unlike a polytunnel you get a comfortable space to enjoy them in. For large-scale crop growing, a polytunnel covers more ground for less money.
Is a dome more durable than a polytunnel?
Far more. Solid, UV-protected polycarbonate lasts for years without tearing, and an anchored dome's geodesic shape spreads wind and snow loads. Polytunnel polythene tears, degrades in UV and typically needs replacing every few years.
Is a polytunnel cheaper?
Yes, much. It's basic growing cover. A dome is a designed garden room, so it costs more, but it does a completely different job and lasts far longer.
Which should I buy?
A polytunnel for serious, large-scale growing on a budget; a dome for a beautiful, lasting room you can also grow and relax in.
Sources: polycarbonate material data from A&C Plastics, Piedmont Plastics and KASTLITE.