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Updated April 2026
Written by the Waldenhaus team
Picture a couple who have already ordered a 6.5ft greenhouse and paid the deposit, then get the chance to stand inside one before it arrives.
They step in, look at each other, and say nothing for a good ten seconds.
Then one of them says, “We’re going to need the 13ft, aren’t we.” The other nods.
They had spent months planning what to grow: tomatoes, cucumbers, a propagation shelf, even a citrus tree nurtured indoors for years. None of it was going to fit in 12.5 square feet.
It is a common scene, and the lesson behind it comes up again and again.
People usually choose a greenhouse size by looking at their garden, picking a number that feels reasonable, and hoping it works out.
Most online guides do not help much. They list dimensions, show you a product table, and take you straight to checkout.
Very few ever show what will actually fit inside.
This guide gives real layout diagrams for each of our five sizes: not rendered marketing images, but proper floor plans showing staging, grow bags, paths, and potting areas.
Scroll to the size you’re considering and you’ll see exactly what you’re getting.
Before we get into it, one important point. The question is rarely “what size greenhouse do I need?”. The better question is “what size will still work for me in two years’ time?”
They’re different questions, and this guide is here to help with both.
Quick Answer: Recommended Sizes at a Glance
If you’re short on time, here’s the simple breakdown:
| Grower Type | Recommended Size | Why |
|---|---|---|
| Beginners / small gardens | 6.5ft (2m) | Gets you started without overwhelming a small plot |
| Keen gardeners | 10ft (3m) | Room for crops and propagation without going large |
| Most popular / families | 13ft (4m) | The sweet spot: rarely do people wish they'd gone smaller |
| Enthusiasts | 16ft (5m) | Space for a wide variety of crops, including citrus and tender plants |
| Serious growers / near self-sufficiency | 20ft (6m) | A complete growing space: crops, propagation, and even seating |
Read on for the detail, especially the size-by-size layouts, as the numbers on paper don’t always reflect what you can actually do inside.
The Rule Everyone Forgets: Internal Width Matters More Than Length
Greenhouses are often listed as “6×8”. This refers to the external footprint in feet.
What most people don’t realise until they step inside is that it’s the width that ultimately determines how usable the space feels.
Here is why.
If you’ve got staging along one wall and grow bags on the floor, you need a workable central path: at least 60cm, ideally 75cm.
What’s left after that determines how wide your staging can be, whether you can fit bags on both sides, and whether two people can work in there comfortably.
All Waldenhaus Nordic greenhouses have an internal width of approximately 1.9m.
That gives you enough space for a grow-bag run on one side, a central path, and staging on the other, or grow bags on both sides if you prefer, although the walkway becomes tighter.
The 45mm Swedish pine frame also doesn’t eat into the usable interior space in the way thinner aluminium systems often do.
By comparison, a typical budget 6ft aluminium greenhouse (usually £400-£600) offers around 1.8m of internal width.
Not a huge difference on paper, just 10cm, but in practice it changes how the space feels and functions.
Aluminium staging brackets also tend to fix you into narrower configurations, which limits how flexible the layout can be.
Plenty of gardeners who have used aluminium greenhouses for years still feel cramped inside. More often than not, the issue is width rather than length.
In the Nordic range, width remains constant across all five sizes. Only the length changes, which means everything below scales in one direction only.
Size-by-Size: What Actually Fits (With Layout Diagrams)
These aren’t theoretical floor plans. Each layout below is based on how the Waldenhaus greenhouses are typically set up in a real garden, with realistic room for staging, grow bags and a working path.
NORDIC-S, 8×6 ft (£999)
Internal space: ~2m × 1.9m = 3.8 sq m
This is our entry point, and it’s a genuine greenhouse, not a cold frame dressed up with a price tag.
You can fit four grow bags, a shelf, and a small staging table. That’s roughly 12 tomato plants, or around 20 peppers if you choose compact varieties.
There’s space for a heated propagator in the corner from February to April. Once you’ve potted things on, it can be moved out, and you’ve got a proper small growing setup.
The honest view: you’ll fill this faster than you expect.
Most people who choose the 2m fall into one of two groups: those with genuinely small gardens (courtyard spaces in cities like Leeds or Bristol, or terraced gardens in places like Norwich where the entire plot may be around 4 metres wide), or those testing greenhouse growing before moving to something larger.
Both are completely valid starting points.
But if you have more space than that, and you’re already thinking about cucumbers, peppers, or even a lemon tree one day, it’s usually worth stepping up a size.
NORDIC-M, 8×10 ft (£1,199)
Internal space: ~3m × 1.9m = 5.7 sq m
This is where things start to become genuinely practical.
You can fit six grow bags, a dedicated propagation area, and still maintain a clear run along one side if you place shelving units at the end. There’s also enough staging for herbs and salad leaves along the back.
In terms of capacity, that’s around 18 tomato plants, plus a good selection of herbs and a couple of trays of cut-and-come-again leaves through the cooler months.
The 3m is a popular step up from the 2m.
Most gardeners already expect the 2m to feel tight. The extra metre is what makes the difference between “just a greenhouse” and a productive growing space.
If budget is a genuine constraint, the 3m is the natural choice.
It’s a solid greenhouse that meets the needs of most hobby growers.
At this size you can grow tomatoes, courgettes, peppers, and even Meyer lemons across multiple seasons before eventually upgrading to a 4m.
By then, most have used every centimetre of the space.
And that’s exactly the point.
NORDIC-L, 8×13 ft (£1,299)
Internal space: ~4m × 1.9m = 7.6 sq m
This is our most popular size, by a clear margin.
The 4m is the size most NORDIC buyers choose, ahead of every other length.
The 7.6 square metres gives you real flexibility.
You can fit around eight grow bags, a potting area, and a propagation shelf with a heated mat, with seed trays running through spring, while still having space to move comfortably.
That’s roughly 24 tomato plants, alongside cucumbers, peppers, and anything else you want to experiment with.
At this point, the growing season becomes genuinely productive rather than a constant juggling act.
Why does everyone choose the 4m?
It’s the point at which greenhouse growing shifts from producing a few tomatoes to genuinely producing food for the household.
You can start seeds in February, keep crops running through summer, and still have bench space for overwintering tender plants in October.
At this size, the greenhouse becomes a year-round growing space rather than a seasonal project.
If you’re deciding between the 3m and the 4m, the 4m is usually the safer choice. The price difference is around £200. The difference in usability is greater.
NORDIC-XL, 8×16 ft (£1,399)
Internal space: ~5m × 1.9m = 9.5 sq m
Nearly 10 square metres of growing space. This is where the greenhouse starts to feel like a proper horticultural space, rather than an extended garden shed.
You’ve got room for around ten grow bags, a full potting bench at one end, and a citrus tree in a pot, the lemon you’ve been meaning to give proper space for the last few years.
In spring, you can also run trays of seedlings without having to rearrange everything else just to make them fit.
A 5m greenhouse will comfortably support a family of four through the summer months with tomatoes, cucumbers, peppers, and courgettes, while still leaving bench space for propagation and overwintering.
It’s also the size where you can dedicate a proper zone to more heat-loving crops such as chillies, aubergines, and sweet peppers, plants that benefit from higher temperatures and more controlled growing conditions.
The temperature stability here is worth a mention.
Larger greenhouses have more air volume, which naturally slows down temperature swings on both hot and cold days.
In 2m and 3m structures, heat can build quickly on a sunny June afternoon. In a 5m, that effect is noticeably reduced.
In exposed areas of the UK, where nights are colder and summer days can be more extreme, a 5m tends to feel more stable than a smaller setup.
That stability makes a real difference for more delicate crops.
NORDIC-XXL, 8×20 ft (£1,549)
Internal space: ~6m × 1.9m = 11.4 sq m
The 6m isn’t for everyone.
If you’re only growing tomatoes and peppers in a medium-sized suburban garden, you probably don’t need 11 square metres of greenhouse space.
But if you’ve ever owned a smaller greenhouse and found yourself planning crop rotations and wishing for more room, the appeal becomes obvious.
Twelve grow bags in two rows, a full potting and seeding bench, and a heated mat for propagation from January onwards.
There’s also space for a seating corner, and some gardeners do add an armchair once the growing is sorted.
You can fit a dwarf fruit tree or two as well.
This is the size where people stop thinking of the greenhouse as a growing space and start thinking of it as somewhere they actually want to spend time.
At 6m there is finally enough room to run proper succession planting without everything becoming chaotic, the kind of setup a grower with decades behind them tends to want.
Lettuces starting while tomatoes are still producing. Overwintered herbs and tender perennials at one end, summer crops in the middle, propagation at the other.
It runs as a system.
That’s the 6m.
What Most UK Greenhouse Guides Won't Tell You
The most common regret: wishing they'd gone bigger
It's the most common regret you'll hear from greenhouse owners: wishing they'd chosen bigger the first time.
The most common regret in greenhouse buying is starting too small.
It’s a pattern you see consistently.
The couple at the start of this guide is a typical example.
Cost per square metre drops as you go bigger
One factor that’s often overlooked when comparing sizes is that the cost per square metre decreases as you scale up.
The 2m works out at roughly £395 per square metre. The 6m is closer to £167 per square metre.
Most of the cost is tied up in the structural frame, glazing, hardware, and anchoring system, which remain largely fixed regardless of length. Adding length is relatively inexpensive once that base structure is in place.
If budget is a deciding factor between two sizes, this relationship is worth considering.
Planning permission: what you actually need to know
In England, greenhouses with an eaves height under 2.5m typically fall under permitted development, meaning planning permission is not usually required. This covers all Nordic sizes.
Scotland, Wales, and Northern Ireland have slightly different rules, and properties in conservation areas or Areas of Outstanding Natural Beauty (AONB) should always be checked with the local planning authority.
This is general guidance and not legal advice.
Our EasyMount system anchors directly into ground stakes, meaning a concrete base is not required. This also classifies the structure as temporary in most local authority interpretations, which can reduce planning complexity.
If you’re placing a greenhouse on an allotment, most associations allow structures below certain footprint limits without prior approval, but you should always confirm with your specific allotment rules or tenancy agreement.
Wind exposure matters, a lot
If you’re on a hillside, coastal site, or otherwise exposed location, structural integrity matters more than size.
Lightweight polycarbonate greenhouses are among the first garden structures to suffer in severe weather: panels can pop out and frames flex in strong gusts, which is why anchoring and frame strength matter most on open, exposed plots. The NORDIC uses a 45×45 mm FSC-certified Swedish pine frame with steel-reinforced joints and a galvanised ground-screw anchoring system, engineered for British storm conditions.
In exposed environments, a lightweight aluminium frame will be a limiting factor regardless of size.
Factor this into your decision if you’re not in a sheltered urban garden.
If you're also weighing up glazing options, our polycarbonate vs glass article covers the practical differences in detail. And if you're still deciding between timber and aluminium frames, the wooden vs aluminium article is worth a read before you commit.
How to Actually Measure Your Space
This sounds obvious, but people get it wrong regularly. Here's the practical checklist:
Leave 60cm around all sides. You need access to clean panels, inspect the base, and re-secure anchors after strong weather. Tight installations against fences or walls can look fine initially, but make maintenance difficult later. 60cm is the minimum, 75cm is more comfortable.
Orient the long side south where possible. This maximises light exposure through the main glazed face. Ideally, the ridge runs east-west so the long sides face south and north. This isn’t always achievable depending on garden layout, but even partial southern exposure improves light levels, particularly in autumn and winter.
Avoid overhanging trees. Trees create both shading and physical risk. Falling branches can damage polycarbonate panels in storms, while leaf build-up reduces light transmission and can encourage algae growth in shaded areas. Where possible, position the greenhouse outside the canopy line.
Check for underground services.
Before installing ground anchors or any form of base, confirm what lies beneath the surface. A basic cable detector or a check via a utility mapping service such as Digdat helps avoid issues later.
Standard greenhouse sizes in the UK explained
Before matching a greenhouse to your garden, it helps to know the standard greenhouse sizes sold in the UK. Most manufacturers build to a small number of common footprints, quoted in feet, with width and length almost always sold in even increments. The table below sets out the standard UK greenhouse sizes, their approximate metric footprint, internal floor area and the type of grower each one typically suits.
| Standard size (ft) | Approx. metric | Floor area | Typical use |
|---|---|---|---|
| 4×6 ft | 1.2 × 1.8 m | ~2.2 m² | Smallest common size; propagation and a few plants |
| 6×4 ft | 1.8 × 1.2 m | ~2.2 m² | Compact starter; tight for staging plus floor crops |
| 6×6 ft | 1.8 × 1.8 m | ~3.3 m² | The classic UK starter footprint |
| 6×8 ft | 1.8 × 2.4 m | ~4.4 m² | Most popular small size; staging plus grow bags |
| 8×6 ft | 2.4 × 1.8 m | ~4.4 m² | Wider walk-in feel in a small footprint |
| 8×8 ft | 2.4 × 2.4 m | ~5.8 m² | Mid-range; comfortable for a keen gardener |
| 8×10 ft | 2.4 × 3.0 m | ~7.2 m² | Family growing; the common step-up size |
| 8×12 ft | 2.4 × 3.7 m | ~8.9 m² | Productive household supply |
| 10×12 ft+ | 3.0 × 3.7 m | ~11 m²+ | Enthusiast and near self-sufficiency |
The width is the figure that decides how usable a greenhouse feels. The most common UK greenhouse width is 6 ft (around 1.8 m), which leaves a narrow central path once staging is in place. An 8 ft (around 2.4 m) width gives a noticeably more workable layout for staging down one side and grow bags or pots on the other. Every Waldenhaus NORDIC greenhouse is built on an 8 ft wide footprint with roughly 1.9 m of internal width, then offered in five lengths from 8×6 ft up to 8×20 ft.
Every Waldenhaus NORDIC greenhouse is built on an 8 ft wide footprint with roughly 1.9 m of internal width, then offered in five lengths from 8×6 ft up to 8×20 ft.NORDIC greenhouse size comparison table
| Size | Internal Area | Grow Bags | Plants (approx) | Best For | Price |
|---|---|---|---|---|---|
| Nordic 2m | 3.8 sq m | 4 | ~12 tomatoes / 20 peppers | Small gardens, first greenhouse | £999 |
| Nordic 3m | 5.7 sq m | 6 | ~18 tomatoes + herbs | Keen growers, budget-conscious | £1,199 |
| Nordic 4m | 7.6 sq m | 8 | ~24 tomatoes + cucumbers + peppers | Families, anyone not wanting to upgrade | £1,299 |
| Nordic 5m | 9.5 sq m | 10 | Family of 4 + tropicals/citrus | Enthusiasts, variety growers | £1,399 |
| Nordic 6m | 11.4 sq m | 12 (2 rows) | Full growing station + trees | Serious growers, self-sufficiency | £1,549 |
Frequently Asked Questions
What are the standard greenhouse sizes?
UK greenhouses are sold in a handful of standard sizes, almost always quoted in feet and in even increments. The most common greenhouse sizes are 6×4 ft, 6×6 ft, 6×8 ft, 8×6 ft, 8×8 ft, 8×10 ft and 8×12 ft, with larger 10 ft and 12 ft wide models available for enthusiasts. Width matters more than length: 6 ft (about 1.8 m) is the most common width, while 8 ft (about 2.4 m) gives a far more workable internal layout. As a rough guide, a 6×8 ft greenhouse offers around 4.4 m² of floor space, an 8×10 ft around 7.2 m², and a 10×12 ft around 11 m².
What is the average greenhouse size in the UK?
There is no single official figure, but across the UK the most commonly bought domestic greenhouses cluster around 6×8 ft and 8×8 ft, roughly 4 to 6 m² of floor space. Smaller 6×4 ft and 6×6 ft models are popular as first greenhouses, while 8×10 ft and larger sizes are typically chosen by families and keen growers. In practical terms, many buyers find they want a little more space than they first plan for, which is why an 8 ft width is a sensible baseline for most gardens.
What size greenhouse do I need for tomatoes?
For tomatoes alone, a 2m or 3m greenhouse is sufficient. You can typically fit 12-18 tomato plants depending on variety.
However, most growers eventually expand into cucumbers, peppers, and herbs alongside tomatoes, in which case the 4m becomes the more practical baseline.
Standard indeterminate tomato varieties grow tall and benefit from generous height clearance, which the Nordic ridge design accommodates well.
If you’re using grow bags (the most common approach in the UK), plan for around three plants per bag and roughly two bags per metre of length.
Do I need planning permission for a greenhouse in the UK?
In most cases in England, no. A greenhouse is considered permitted development, provided it is under 2.5m in eaves height and does not cover more than 50% of the garden area.
All Waldenhaus Nordic greenhouses fall within these thresholds.
Rules differ in Scotland, Wales, and Northern Ireland, and additional restrictions may apply in conservation areas or listed building curtilages. Always confirm with your local planning authority if you are unsure.
Our EasyMount anchoring system (which does not require a concrete base) means the structure is generally treated as temporary in many local interpretations, which can further simplify planning considerations.
This is general guidance and not legal advice.
What size greenhouse do I need for a family of 4?
For a family of four looking to meaningfully supplement their diet with homegrown produce, the 4m or 5m range is typically most appropriate.
The 4m (approximately 7.6 sq m) supports a productive summer crop of tomatoes, cucumbers, and peppers, with additional capacity for propagation in spring.
The 5m adds further flexibility, including space for a potting bench and a wider range of crops such as aubergines, citrus, or seasonal flowers.
For near self-sufficiency in vegetables during the growing season, the 6m provides a more capable setup.
Is a 6x4 greenhouse too small?
A 6x4ft greenhouse (approximately 1.8m x 1.2m, around 2.2 sq m) is quite limited in practical growing space.
It can be used for propagation and a small number of plants, but it does not comfortably accommodate standard grow bags and offers restricted working room.
Industry guidance from organisations such as the RHS suggests a minimum of around 6ft wide (1.8m) for basic usability, with 8ft (2.4m) being more practical for productive layouts with staging.
Can I extend my greenhouse later?
Our Nordic range is not modular, meaning it cannot be extended after installation.
For this reason, it is worth considering future requirements at the point of purchase.
In practice, many buyers find that an additional increment in size at the outset provides far better long-term usability than upgrading later.
What’s the best greenhouse size for an allotment?
For allotment use, the 4m or 5m is typically the most practical choice.
Allotment gardeners tend to grow more intensively, which makes the additional staging and propagation capacity genuinely useful.
However, allotment rules vary by association, so it is important to confirm permitted structure size and placement before installation.
Sources & further reading
- Planning Portal: Outbuildings, the official permitted development rules for garden buildings in England, source of the 2.5 m eaves limit quoted in this guide.
- HSE: Avoiding danger from underground services (HSG47), the safety guidance behind our advice to check for buried services before you drive a ground anchor.
- Met Office: Wind, background on why exposed plots see far stronger gusts than sheltered gardens.
- Forest Stewardship Council: What the FSC labels mean, what FSC certification tells you about where the timber in a greenhouse frame comes from.
Read next: Wooden Greenhouse Buying Guide UK 2026: the 9-step buyer's checklist
Read next: Small Wooden Greenhouse, NORDIC S · Wooden Greenhouse Maintenance: the real schedule
Going larger? See our Large Wooden Greenhouse landing for NORDIC L/XL/XXL details.
Now plan the growing: How to grow tomatoes in a UK greenhouse (includes realistic yields per NORDIC size).
Choose your NORDIC wooden greenhouse
By size
- 8×6 ft, NORDIC-S £999 · patio / starter / small allotment
- 8×10 ft, NORDIC-M from £1,199 · family veg garden sweet spot
- 8×13 ft, NORDIC-L from £1,299 · serious year-round growing
- 8×16 ft, NORDIC-XL from £1,399 · multi-crop with two ground beds
- 8×20 ft, NORDIC-XXL from £1,549 · walk-in / market grower
By configuration
- Lean-to wooden greenhouse · wall-mount, space-efficient
- Polycarbonate greenhouses UK · 4 mm CrystalLight glazing detail
Decide before you buy
- Greenhouse Buying Guide UK 2026 · full step-by-step framework
- Wooden Greenhouses overview · the NORDIC range explained
- Shop the NORDIC range, from £999
