What size greenhouse do I need? UK sizes in feet and metres
The number that decides what you can grow is the width. Width settles whether you get a bed on each side of a path or a single bench along one wall; length only adds more of the same. So choose the width for the way you want to work, then add length for the plants you want, and check the plot, the base and the planning rules before you settle on a size.
- Width first. At 2.6 m (NORDIC) or 3 m (Plot 3.14) there is room for a bed each side of a central path; narrower houses suit one bed and staging.
- Length for plants. At the RHS spacing of 45 to 60 cm, each metre of bed takes about two cordon tomatoes.
- Measure the whole footprint. The greenhouse, plus the base, room to work round it and the planning distance from the boundary.
What are the common greenhouse sizes in the UK?
Most are sold in feet: 6 × 4, 6 × 8, 8 × 6, 8 × 10 and up. In metres, a 6 × 4 ft greenhouse covers about 2.2 m², a 6 × 8 ft about 4.5 m² and an 8 × 10 ft about 7.4 m².
| Size in feet | In metres, about | Floor, about | Suits |
|---|---|---|---|
| 6 × 4 ft | 1.8 × 1.2 m | 2.2 m² | Seedlings and a few pots |
| 6 × 8 ft | 1.8 × 2.4 m | 4.5 m² | One bed and staging |
| 8 × 6 ft | 2.4 × 1.8 m | 4.5 m² | A short bed either side of the door |
| 8 × 10 ft | 2.4 × 3.0 m | 7.4 m² | Two beds and a path |
| 10 × 13 ft | 3.0 × 4.0 m | 12 m² | Two long beds, a path and staging |
| 10 × 20 ft | 3.0 × 6.1 m | 18.6 m² | A season of crops for a household |
Greenhouses are usually quoted width first, but not always, so check which side is which on the drawing before you compare two listings.
Why does width matter more than length?
Width sets the layout. With enough width you get beds on both sides and a path you can walk and kneel in; without it, you have one bed and a narrow aisle.
Both of ours take a bed down each side with a central path: NORDIC is 2.6 m wide, and Plot 3.14 stands 3.00 m wide on the ground. Narrower models suit a single bed along one side, with staging or pots opposite. Adding length doubles nothing about the layout; it simply repeats it, which is why choosing the width comes first.
| Clear width inside | Path | Left for beds | Arrangement to try |
|---|---|---|---|
| 1.7 m | 0.75 m | 0.95 m | One bed and a bench, or staging |
| 2.4 m | 0.75 m | 1.65 m | Two beds of about 0.8 m |
| 2.8 m | 0.9 m | 1.9 m | Two beds of about 0.95 m |
Test the reach with empty pots and a board for the bench before you plant: can you reach the back, turn round and water the far corner?
Height matters too. A tall ridge gives room to train cordon tomatoes and cucumbers upwards: NORDIC rises to 2.3 m at the ridge and 1.51 m at the eaves, and Plot 3.14 to 2.02 m at the top of the arch.
How many tomato plants fit in a greenhouse?
At the RHS spacing of 45 to 60 cm, about two cordon tomatoes per metre of bed. A 3 m greenhouse with a bed on each side takes about ten to twelve.
The RHS tomato guide spaces plants 45 to 60 cm apart, depending on their eventual size. Leave about 30 cm at each end of a 3 m bed and it holds five plants at 60 cm or six at 45 cm, so two beds hold ten to twelve. In containers, the RHS puts one plant in a 30 to 45 cm pot and two in a standard growing bag. Leave room for the rest of the summer: a few peppers, cucumbers on a string, basil at the front. Our compact vegetables guide suggests crops that suit a small house.
What sizes do NORDIC and Plot 3.14 come in?
NORDIC: 2.6 m wide, 2 to 6 m long, from 8 × 6 ft. Plot 3.14: 3.00 m wide on the ground, 4 to 12 m long, from 10 × 13 ft.
| Model | Size | Floor | Price |
|---|---|---|---|
| NORDIC-S | 2 m long, 8 × 6 ft | 5.2 m² | £999 |
| NORDIC-M | 3 m, 8 × 10 ft | 7.8 m² | £1,099 |
| NORDIC-L | 4 m, 8 × 13 ft | 10.4 m² | £1,199 |
| NORDIC-XL | 5 m, 8 × 16 ft | 13.0 m² | £1,299 |
| NORDIC-XXL | 6 m, 8 × 20 ft | 15.6 m² | £1,399 |
| Plot 3.14, 4 m | 10 × 13 ft | 12 m² | £899 |
| Plot 3.14, 6 m | 10 × 20 ft | 18 m² | £1,099 |
| Plot 3.14, 8 m | 10 × 26 ft | 24 m² | £1,299 |
| Plot 3.14, 10 m | 10 × 33 ft | 30 m² | £1,599 |
| Plot 3.14, 12 m | 10 × 39 ft | 36 m² | £1,799 |
Plot 3.14 extends in 2 m sections, made to order, and NORDIC comes in five set lengths. Delivery is in 1–4 weeks from order, to the kerb.
How do you check that a greenhouse fits your garden?
Peg out the base size from the plan, which is larger than the greenhouse, then add room to work round it, the door swing and the distance the planning rules need from the boundary.
- Find the base size for the model and length on its base plan.
- Peg it out where the greenhouse will stand and check both diagonals.
- Add room to work all round: NORDIC’s manual asks for about 0.5 m beyond the base, more at the door end.
- Check the distance to fences and buildings: both manuals ask for 2 m clear.
- Check the height near the boundary against the planning rules for your nation.
- Walk the route from the kerb with the pallet size in mind.
Our base guide lists the base for every NORDIC and Plot 3.14 length, and the planning guide covers the height and position rules in all four nations.
Can you make a greenhouse bigger later?
Plot 3.14 extends in 2 m sections, made to order. NORDIC comes in five fixed lengths, so choose its size for the garden you will have in a few years.
If you are between two sizes, the extra length costs less per square metre: on the prices above, a 6 m Plot 3.14 costs about £61 per m² against about £75 for the 4 m. Weigh that against the space it takes from the garden.
Quick answers about greenhouse sizes
For seedlings, a few pots and some salad, it works. For tomatoes and cucumbers through the summer, a bed on each side needs a walk-in width such as NORDIC’s 2.6 m.
At 45 to 60 cm apart, about two cordon plants per metre of bed. Ten to twelve plants need two 3 m beds.
About 2.4 × 1.8 m, roughly 4.5 m² of floor. NORDIC-S is 2.6 × 2 m, a little larger, with 5.2 m².
Size alone doesn’t decide it: height near the boundary, position and the share of the garden do. Our planning guide sets out the rules for each nation.
What should you know before choosing a size?
The width you need for your layout, the length for your plants, the base size, room to work, the boundary distance and the budget per square metre.
Six checks on size
Tick them off with a tape measure in the garden. Your ticks stay on this device.
Compare NORDIC lengths side by side
The NORDIC page shows every size with its base plan and price. An expert can help you fit it to your garden.
What we checked for this guide
Sizes and prices come from the NORDIC and Plot 3.14 product pages on 20 October 2026; plant spacing from the RHS. Checked 20 October 2026.
Related guides
Written by the Waldenhaus team. We sell outdoor saunas and greenhouses and write these guides from manufacturer manuals, official guidance and our own product pages. Where your equipment manual says something different, follow the manual.