4mm — Best Value
A great all-round choice for most UK gardens. Excellent light transmission and the most economical option.
Choose 4mm if: you want the best balance of performance and price.
Black Friday Price Guarantee
Order now with confidence. If the same greenhouse model, size and specification is advertised at a lower price on polyecogreenhouses.com during our guarantee period, you can claim the difference back.
How It Works →Eligible orders from 3 October 2026. Claims close 11:59pm, 6 December 2026. T&Cs apply.
4mm or 6mm Polycarbonate?
Both options use the same heavy-duty Polyeco Classic steel frame. The main difference is insulation and price.
6mm — Better Insulation
The thicker polycarbonate provides improved insulation and heat retention, making it a good choice for customers wanting a little more protection from colder temperatures.
Choose 6mm if: insulation and extending the growing season are more important to you.
Still unsure? For most customers, 4mm is perfectly suitable. Choose 6mm if you specifically want the additional insulation.
Why Choose The Tube?
The Tube is a practical choice for customers who value usable internal space and a simple, open layout
Clear, Open Interior
With no internal support bars, the Tube gives you uninterrupted growing space from side to side, making it easy to arrange beds, shelving and walkways.
Panels That Stay Put
Durable polycarbonate sheets are securely fixed to the frame, creating a strong and practical greenhouse cover.
No Base Required
The Classic can normally be installed directly onto suitable soil or grass using its ground anchoring system.
Room to Grow
3 metres wide and available in a range of lengths, giving you plenty of growing space without wasting your garden.
Space You Can Actually Use.
The Tube keeps the inside simple. With no internal support bars crossing the greenhouse, the full width stays open for growing beds, shelving, tall crops and easy movement from end to end.
It is a practical design for gardeners who would rather use the space for plants than structural bracing.
Simple structure. Clear interior. More usable growing space.
Dimensions & Specifications
| Width | 3 metres |
|---|---|
| Available lengths | 2m, 4m, 6m, 8m, 10m and 12m and longer* |
| Height | Approximately 2.15 metres |
| Frame | 20mm x 20mm galvanised steel tubes |
| Cover | 4mm or 6mm twin-wall polycarbonate |
| Arch spacing | 67cm |
| Door | Stable-style door |
| Rear ventilation | Included |
| Very exposed sites | The Classic is recommended instead |
| Concrete base required | No, when installed on suitable soil or grass |
Need a longer greenhouse? Please contact us — longer Classic models are available.
What’s Included
- Galvanised steel greenhouse frame
- 4mm or 6mm twin-wall polycarbonate cover, depending on selected option
- Stable-style door
- Rear ventilation window
- Ground anchoring system
- All required greenhouse fixings and fittings
- Assembly instructions
Optional extras such as automatic roof vents, shelving, raised beds and additional doors are available separately.
Complete Your Classic
A few useful extras can make your greenhouse even more practical. Add them now or upgrade your Classic later.
Automated roof vent The Tube
£129.00
Helps regulate temperature and ventilation automatically.
View accessory
Hanging Shelf Polyeco 0,75m x 0,42m
£45.00
Add useful growing and storage space without taking up valuable floor area.
View accessory
Raised Galvanised Steel Flowerbed, 0,75m x 1,5m x 0,3m Silver (not painted)
£89.00
Create a tidy, practical growing area inside your greenhouse.
View accessory
The Tube Rear Doors
£55.00
Add easier access from both ends of longer Classic greenhouses.
View accessory
Accessories are optional extras and are not included with the standard greenhouse unless stated otherwise. Please check compatibility with your chosen Classic size before ordering.