Alton Octagonal Greenhouse
$19,250.00
Features
- Unique octagonal cedar-and-glass design creates a striking focal point with a bright, open feel
- Grade A, knot-free Western Red Cedar for natural insulation, rot resistance, and long-term durability
- Precision joinery keeps the structure rigid, square, and well-aligned over time
- Aluminum base frame lifts cedar off the ground to help reduce early rot risk
- 3mm tempered safety glass for a bright growing environment
- Aluminum capping + rubber seals help protect glazing points and improve weather resistance
- Automatic roof vent openers + louver vents support airflow without needing electricity
- Cedar tones naturally vary piece to piece and will weather to a graceful silvery gray over time
What's Included
- Cedar frame + glass panels + hardware
- Aluminum base frame & capping
- 2x Roof vents with automatic openers
- 2x Louver windows
- Lockable hinged double door
- Shelves: 12" deep (2-slat) on end+ 20" deep (4-slat) in a U-Shape
- Gutters + downspouts
Dimensions
9’2″ W x 11’10” L x 9’8″ H
Shipping
- Ships via LTL freight (curbside): Liftgate + pallet jack delivery; plan 2–3 people to move boxes off the pallet and into place.
- Lead time: 5–7 business days (in stock). Up to 12 weeks (if not in stock).
Assembly & Warranty
- Average assembly time: approx. 2-3 days with 2-3 people
- Assembly Manual: Download here
- 10-year warranty on the cedar framing
Secure Checkout
Nationwide Delivery
Veteran-Owned
Real Greenhouse Owners
Personalized Planning Help
Description
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The Alton Octagonal Greenhouse is for someone who wants more than a standard greenhouse shape. Its octagonal layout creates a sculptural, eye-catching presence that feels just as suited for relaxing as it does for growing — and the Grade A Western Red Cedar frame adds warmth, character, and natural resilience that aluminum simply can’t match.
It’s a greenhouse that feels like part of the garden rather than something placed in it.
Distinctive Octagonal Character
The Alton Wooden Octagonal Greenhouse stands out immediately for its uncommon shape. Instead of the typical straight run of a standard greenhouse, its octagonal layout creates a more unique presence that feels just as suited for relaxing as it does for growing.
The extra facets also help the structure feel bright and visually open from multiple angles. It has the kind of shape that naturally becomes a garden focal point rather than simply blending into the background.
Because this is real cedar, you’ll also see natural variation from piece to piece. Some boards may appear lighter or darker than others, and over time the wood can weather to a soft silvery gray if left untreated. That changing color is part of the natural beauty and charm people love about cedar structures.
Why Cedar Performs So Well
Western Red Cedar offers more than just a beautiful look. It insulates better than aluminum, which can help reduce temperature swings and create a more stable growing environment throughout the day and night.
It is also naturally rot-resistant thanks to its preservative oils, which help deter insects and pests. Cedar can absorb moisture without warping, dries quickly, and holds up for many years with relatively little maintenance—making it a smart material for a greenhouse built for long-term use.
Built for Long-Term Durability
The Octagonal combines several important details that help the structure hold up well over time. Its aluminum base frame helps keep the wood raised off the ground, while aluminum capping protects key exterior areas exposed to weather.
Strong cedar framing and precision joinery also help the greenhouse stay rigid, square, and well aligned as the years go on. That matters in everyday use too—when a structure stays true, doors, vents, and glazing all keep working the way they should.
A Tall Shape With Flexible Uses
At 9’8″ high, the Octagonal feels tall, airy, and more open than many smaller garden greenhouses. That added height makes the space feel more comfortable to work in and can also be useful for hanging baskets, taller plants, or creating a greenhouse that feels a little more like a garden room.
Because the shape opens up differently than a typical rectangular layout, it can also feel especially pleasant for mixed use—gardening, potting, displaying plants, or simply enjoying the space
Easy Access in Every Season
A tall inward-swinging hinged door gives the Octagonal a practical advantage many greenhouses do not have.
On snowy days, the inward swing can make access easier since you do not have to clear the entrance perfectly just to open the door. The low threshold also makes it easier to move pots, trays, and tools in and out with fewer obstacles.
Ventilation That Works Without Power
The Octagonal includes roof vents with automatic wax openers, so they begin opening as temperatures rise—without electricity and without constant adjustment.
Louver windows bring in lower airflow to support circulation and help manage heat and humidity. Together, they create a simple passive ventilation system that feels practical for everyday growing.
Gallery
Other available sizes for special order
Quick Size Guide
Peak height: 9’8″
Sidewall height: 6’2″
Roof pitch: 45°
Dimensions: 9’2″ W x 11’10” L x 9’8″ H
Every Alton Wooden Octagonal Greenhouse kit includes:
- Western Red Cedar framing
- 3mm tempered glass
- Aluminum base frame
- Aluminum capping
- Lockable double hinged door (+ keys)
- 2x Roof vents (23″ x 23″) + auto openers
- 2x Louver windows (31″ x 41″) + manual openers
- Shelving: 12″ deep (2-slat) for the back + 20″ deep (4-slat) in a U-shape
- Gutters + downspouts
- Hardware
Specifications
| Brand | Alton |
|---|---|
| Distributed by | Exaco |
| Made in | UK |
| Width | 9' |
| Length | 12' |
| Floorspace | 101 sq ft |
| Peak Height | 9'8" |
| Side Wall Height | 6'2" |
| Framing Material | Aluminum, Western Red Cedar |
| Frame Color | Moss Green, Natural Wood |
| Roof Glazing | 3mm tempered glass |
| Wall Glazing | 3mm Tempered Glass |
| Roof Pitch | 37° |
| Roof Vent Opener Type | Automatic (wax) |
| Roof Vent Dimensions | 24" x 19" |
| Door Type | Double, Hinged |
| Door Dimensions | 57" x 72" |
| Foundation Frame | Integrated Base |
| R-Value | 0.95, 1.35 |
| Rainwater Collection | Yes |
| Stem Wall Compatibility | No |
| Expandable | No |
| Warranty | 10 years on frame |
What foundation do I need?
Picking a level site is the best first step. It is important that the foundation is level and strong enough to hold the greenhouse. A concrete slab or a concrete perimeter wall will provide the most solid, long-lasting base. The key is that your foundation is level, square, and well-draining—even small twists can affect door operation and panel fit.
Helpful guides:
Does cedar color vary?
Yes — and that’s normal. Cedar is a natural material, so boards will vary in tone (light honey to deeper reddish shades) and grain pattern. Over time, cedar also weather-shifts if left unfinished.
Do I need to paint or treat it?
No. All Alton greenhouses are made from naturally rot-resistant Western Red Cedar and come factory-treated with a clear preservative. You don’t need to stain or re-treat it for rot protection—most owners just do a yearly clean. If you want a specific color or want to slow the natural silvery aging, you can apply a stain/preservative (easiest before assembly).
Do the roof vent openers require electricity?
No. They are wax-cylinder openers, which expand and contract with temperature to open/close the vent—so there’s no wiring and no power required.
Are There any accessories I should add?
The Octagonal already includes shelving for one sidewall. Beyond that, we always recommend adding an exhaust fan because greenhouses can heat up very quickly in direct sunlight—even on mild days. If you plan to use the greenhouse in winter, you may need a heater as well.
Where does this ship from?
Austin, Texas
How Does Curbside Delivery Work?
Freight delivery drops your crate at the curb/end of driveway. Typically, you’ll unload the contents with the driver and the crate remains on the truck. If you have a forklift or tractor with long forks, you may be able to lower the whole crate using the liftgate. Plan for 2–3 people to help.
Tip: Make sure the truck can access your driveway and you have a clear staging area ready.
Made by
Alton: 100+ years of craftsmanship
Alton Cedar Greenhouses has built traditional timber greenhouses in the UK since 1921, known for classic design, careful joinery, and cedar construction that’s made to last.
Explore Alton GreenhousesDistributed by
Exaco
Exaco is the authorized North American distributor for Alton, known for importing a curated lineup of high-quality European garden products—and for support that goes the extra mile.
More About ExacoReviews
Additional information
| Distributed by | Exaco |
|---|---|
| Door Type | Double, Hinged |
| Expandable | No |
| Floorspace | 101 sq ft |
| Foundation Frame | Integrated Base |
| Frame Color | Moss Green, Natural Wood |
| Framing Material | Aluminum, Western Red Cedar |
| Length | 12' |
| Made in | UK |
| Peak Height | 9'8" |
| R-Value | 0.95, 1.35 |
| Rainwater Collection | Yes |
| Roof Glazing | 3mm tempered glass |
| Roof Pitch | 37° |
| Roof Vent Dimensions | 24" x 19" |
| Roof Vent Opener Type | Automatic (wax) |
| Side Wall Height | 6'2" |
| Wall Glazing | 3mm Tempered Glass |
| Warranty | 10 years on frame |
| Width | 9' |
| Style | Octagonal |
| Stem Wall Compatibility | No |
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