A cedar greenhouse is a greenhouse framed in cedar wood, most often Western Red Cedar, which resists rot on its own and looks warm and natural in a garden. It costs more than an aluminum kit and needs a fresh coat of treatment every few years. With that care, a well-built cedar greenhouse can last for decades.
We sell Alton cedar greenhouses, made in the UK, and we help customers choose between wood and aluminum every week. This guide covers how cedar performs, what it costs, how to look after it, and which Alton model fits your yard.
โ Quick answer
- Cedar is a top wood for greenhouses because its heartwood naturally resists rot and insects.
- Wood frames lose heat more slowly than metal frames, so a cedar greenhouse feels warmer to work in.
- The trade-offs: a higher price, thicker frame bars, and a wood treatment about every 3 years.
- Alton models use Grade 1 Western Red Cedar with an aluminum base, and are guaranteed not to rot for 10 years.
- Best for gardeners who want a greenhouse that doubles as a beautiful garden room.
What is a cedar greenhouse?
A cedar greenhouse uses cedar timber for its frame instead of aluminum, steel or plastic. The glazing is usually glass, held in the wooden glazing bars. Most quality kits use Western Red Cedar, a softwood that grows in the Pacific Northwest and western Canada.
Cedar has been used outdoors for generations, from shingles to fences to garden buildings. The reason is simple. Its heartwood contains natural compounds that make it hard for rot and many insects to break down. That means the wood can stand up to the damp air inside a greenhouse without heavy chemical treatment.
Why is cedar good for a greenhouse?
Our customers usually choose cedar for a mix of practical and personal reasons. Here are the main ones.
- Natural rot resistance: greenhouses are warm and humid. Cedar heartwood handles that better than most common woods, like pine.
- A warmer frame: wood conducts heat far more slowly than aluminum. The frame doesn't turn icy on cold nights, and it feels pleasant to the touch.
- Strength without bulk: cedar is light for its strength. It holds screws well and keeps its shape as the weather changes.
- Beauty: the warm color and grain blend into a garden. Many owners use theirs as a sitting room as well as a growing space.
- A renewable material: wood is a renewable resource when it comes from responsibly managed forests.
๐ก Our tip: the glass does most of the heat loss in any glass greenhouse, not the frame. So a cedar frame helps, but you will still need heat in winter in cold regions. Our guide on the cost to heat a greenhouse in winter shows real numbers by size.
What are the downsides of a cedar greenhouse?
Cedar is not the right choice for everyone. Be honest with yourself about these points before you buy.
- Price: a cedar greenhouse costs more than an aluminum one of the same size.
- Upkeep: the wood needs a protective treatment every few years to keep its color and protection.
- Thicker frame bars: wood bars are wider than slim aluminum bars. They cast a little more shade on your plants.
- Color changes: left untreated, cedar slowly weathers to a silver-gray. Some people love that look, and some don't.
- Natural variation: each piece of wood differs in color, from light to dark.
Here is how cedar compares with an aluminum glass greenhouse, such as our Janssens Royal Victorian range.
| Feature | Cedar (Alton) | Aluminum (Janssens) |
|---|---|---|
| Look | Warm, natural wood | Slim black or green frame |
| Frame feel in winter | Stays warmer | Gets cold to the touch |
| Light | Wider bars, a bit more shade | Thin bars, more light |
| Glass | 3mm toughened glass | 4mm tempered glass |
| Upkeep | Wood treatment about every 3 years | Wash the frame and glass |
| Cost | Higher | Lower for the same size |
For the full picture, read our guide to wooden vs aluminum frame greenhouses.
How long does a cedar greenhouse last?
It depends on the wood grade, the design and your care. Alton designs its frames to keep water away from the timber. The product pages state that Alton greenhouses are guaranteed not to rot for 10 years.
Alton recommends treating the wood every 3 years. With that routine, the manufacturer estimates a lifespan of 30 to 50 years. That is an estimate, not a promise, but it shows what good cedar can do.
Simple cedar care routine
- Each spring: wash the glass and wipe down the frame with mild soapy water.
- Each fall: clear leaves from the gutters and check that the doors and vents move freely.
- Every 3 years: brush on a wood treatment made for exterior cedar, on a dry day.
- Any time: keep soil, mulch and standing water away from the wood.
๐ Note on warranties: most Alton models carry a 10-year limited warranty, and the Cheltenham product page lists 15 years. Always check the product page for the model you choose, and keep your treatment routine.
What makes an Alton cedar greenhouse different?
Not all cedar greenhouses are built the same way. These are the features listed on our Alton product pages:
- Wood: Grade 1 Western Red Cedar from Canada, dipped and sealed, with no knots.
- Frame: thick glazing bars made from 44 x 44mm timbers, or 44 x 69mm in places.
- Joinery: mortise-and-tenon and tongue-and-groove joints with stainless steel hardware.
- Weather protection: aluminum capping on top, plus an aluminum base frame that lifts the wood off the ground.
- Bracing: knee-brace spandrels at every rafter joint, at both the ridge and the gutters.
- Glass: single, large panes of 3mm toughened glass instead of small overlapping pieces.
- Included: shelving, gutters and downpipes on both sides, a hinged door with a lock, and Victorian ridge decorations.
The aluminum base frame is a detail we point out to every buyer. The ground is where wood rots first, so lifting the cedar off it protects the most exposed part of the frame.
Which Alton cedar greenhouse should you choose?
We carry seven Alton cedar models. The table shows the smallest size of each, so you can compare at a glance.
| Model | Sizes offered | Smallest size | Best for | Price guide* |
|---|---|---|---|---|
| Cheltenham | 4 | 8'8" x 12'7", ~108 sq ft | Wood lower wall, cozy feel | from ~$20,328 |
| Lancing | 3 | 10'9" x 16'8", ~179 sq ft | Serious growing space | from ~$26,317 |
| Westminster | 3 | 10'9" x 16'8", ~181 sq ft | Tall Victorian showpiece | from ~$30,145 |
| Durham T-Shaped | 3 | 7'5" x 12'5", ~88 sq ft | Orangery style, smaller yards | from ~$24,882 |
| Cambridge T-Shaped | 3 | 9'10" x 12'5" | Garden room with seating | from ~$26,317 |
| Fusion | 2 (left or right shed) | 10'10" x 10'7", ~115 sq ft | Half greenhouse, half workshop | from ~$18,183 |
| Evolution Octagonal | 1 | 9' x 12' | A garden centerpiece | ~$16,747 |
*Prices checked in October 2026. Prices can change and sales may apply, so click the model name to see today's price.
A quick guide to each model
- Cheltenham: a solid cedar lower wall with glass above. It has a 45-degree roof pitch and a 10' ridge in the smallest size.
- Lancing: a tall growing house with an 11'1" peak, 4 roof windows with automatic openers, and 3 louvered windows.
- Westminster: a classic Victorian shape with an 11'1" peak and 5'7" side walls.
- Durham and Cambridge: T-shaped orangeries that work as sunrooms. The Durham has a low door threshold.
- Fusion: one half is a greenhouse, the other a wood-walled workshop with a 10'7" workbench.
- Octagonal: eight sides, double doors with a low threshold, and aluminum staging in Moss Green.
Love the T-shape? Our article on T-shaped orangeries explains how they live day to day.
How much does a cedar greenhouse cost?
Our Alton cedar greenhouses ranged from about $16,700 to $35,900 when we wrote this (October 2026). Many models had an extra discount already built into the price. The fairest way to compare sizes is cost per square foot.
๐งฎ Formula: cost per square foot
Cost per sq ft = kit price รท floor area (sq ft)
Worked example: the smallest Alton Cheltenham was about $20,328 for about 108 sq ft. That is roughly $188 per sq ft. The smallest Lancing was about $26,317 for about 179 sq ft, or roughly $147 per sq ft. The bigger house costs more in total, but less for each foot of growing space.
The kit is only part of your budget. Plan for these too:
- Foundation: a level base, priced by local contractors.
- Assembly: free if you build it yourself, or a quote from a crew.
- Permits: larger greenhouses often need one, so check with your town.
- Wood treatment: a small cost every few years.
- Heating, fans and shade if you plan to grow all year.
Wondering whether to build your own wooden greenhouse instead? We ran the numbers in is it cheaper to buy a greenhouse kit than build one.
๐ About prices: manufacturers update their prices during the year, and we often run sales and promotions. The price on the product page is always the current one. Prices in this article are a guide from when we wrote it (October 2026), not a quote or guarantee. Found a lower price for the same model at an authorized retailer? We offer a Price Match Guarantee - please check the rules first. Call us and we will confirm today's price and any current deals.
What foundation does a cedar greenhouse need?
Every greenhouse needs a base that is level, square and firm. The Alton aluminum base frame sits on top of that base. Your foundation choice depends on the size of the house and your soil.
- Pick the spot: full sun, good drainage, and room to walk all the way around.
- Choose a base: a concrete slab, a concrete or block perimeter wall, or pavers on compacted gravel.
- Check level and square: measure both diagonals. They should match.
- Anchor it: follow the anchoring steps in the assembly manual.
Our practical guide to a greenhouse foundation walks through each option step by step.
How do delivery and assembly work?
We ship our greenhouses free to the continental US. The kit arrives flat-packed by freight truck, so someone needs to be home to receive it. Tell us about tight roads or low wires before you order.
You can build it yourself with a helper and the manual. Or you can hire one of the independent crews listed on our Assembly Crews page. For the larger models, we often suggest a crew. Big glass panes are heavy, and an experienced team gets the frame square the first time.
Is an Alton cedar greenhouse worth it?
For the right gardener, yes. You get a greenhouse that grows plants well and also looks beautiful. It works as a quiet room in your garden too.
- Choose cedar if looks matter to you, you will use the space as a garden room, and you don't mind a treatment every few years.
- Choose aluminum if you want the most light, the lowest upkeep, or a lower price per square foot. Our Victorian greenhouse collection is a good place to start.
๐ฟ Our verdict: a cedar greenhouse rewards a little care with decades of use. Treat the wood, keep the gutters clear, and build on a solid base. You can browse every model in our Alton cedar greenhouse collection.
Frequently asked questions
Is cedar a good wood for a greenhouse?
Yes. Cedar heartwood naturally resists rot and many insects, which matters in a warm, humid greenhouse. It is also light, stable and attractive. It does need a protective treatment every few years.
How long does a cedar greenhouse last?
Alton greenhouses are guaranteed not to rot for 10 years. If you treat the wood every 3 years, Alton estimates they can last 30 to 50 years. Real life depends on your climate and care.
Do I need to treat a cedar greenhouse?
Alton recommends treating the wood every 3 years. Untreated cedar still resists rot, but it slowly weathers to a silver-gray color. Treatment keeps the warm color and adds extra protection.
Is a cedar greenhouse warmer than an aluminum one?
The frame is. Wood conducts heat much more slowly than aluminum, so it stays warmer to the touch. But glass loses most of the heat in any glass greenhouse, so plan on heating in cold climates either way.
Where are Alton cedar greenhouses made?
Alton greenhouses are made in the UK from Grade 1 Western Red Cedar grown in Canada. We sell them in the US with free shipping to the continental states.
Need help choosing a cedar greenhouse?
We are a small, woman-owned business in Georgia, and we answer every question personally. Tell us your yard size, your climate and how you want to use the space. We will help you pick the right Alton model, confirm today's price and any current sale, and plan your foundation and assembly crew.