Roundups / Best polycarbonate greenhouses

Grow-your-own · UK product comparison

Best greenhouses with polycarbonate glazing compared in 2026

Polycarbonate glazing is a popular choice for garden greenhouses. This roundup compares six models that all use it, from a small timber unit to a premium resin walk-in. The frames differ: one is hardwood, four are aluminium and one is resin. Sizes range from a 120 x 63 cm footprint to 185 x 247 cm, and prices run from £229 to £879. This page is based on desk research of the product details supplied, not hands-on testing.

P&P

Plot & Pot editors
We compare published product details, sizes and materials. These are desk-researched product roundups, not hands-on tests.

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Our stand-out pick

Palram-Canopia Mythos 6x4 Greenhouse, Silver

The Palram-Canopia Mythos 6x4 Greenhouse, Silver is our pick on paper. At £289 it combines twin-wall polycarbonate glazing with a rust-resistant aluminium frame, a hinged door, an opening window and a roof vent. Gutters and a galvanised steel base are also included. It is £65 cheaper than the Hybrid 6x4 in the same footprint, and it carries a 5-year defects and workmanship warranty. This choice comes from comparing the supplied details, not from testing.

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At a glance

Our picks compared

Prices are dated snapshots and can change. Product dimensions are shown as width × depth × height.

Product	Brand	Price snapshot	Retailer	Dimensions	Weight	Frame	Glazing	Shelves	Lids	Assembly	Warranty	Door	Ventilation	Extras	Roof glazing	Wall glazing
Rowlinson Hardwood Mini Greenhouse	Rowlinson	£229.00	One Garden	120 × 63 × 144 cm	30 kg	FSC hardwood	Twin-wall polycarbonate	2	2 lifting lids with adjustable stays	Self-assembly, 1 to 2 hours	12-month parts	—	—	—	—	—
Palram-Canopia Mythos 6x4 Greenhouse, Silver	Palram-Canopia	£289.00	One Garden	185 × 126 × 208 cm	26.5 kg	Rust-resistant aluminium	Twin-wall polycarbonate	—	—	Self-assembly, 2 people, 4 to 6 hours	5-year defects and workmanship	Hinged single door	1 opening window and 1 roof vent	Gutters and galvanised steel base	—	—
Palram-Canopia Hybrid 6x4 Greenhouse, Green	Palram-Canopia	£354.00	One Garden	185 × 126 × 208 cm	27.4 kg	Powder-coated aluminium	Polycarbonate roof and wall panels	—	—	Self-assembly, 2 people, 4 to 6 hours	5-year defects and workmanship	Hinged door	1 opening window	—	—	—
Palram-Canopia Mythos 6x6 Greenhouse, Silver	Palram-Canopia	£334.00	One Garden	185 × 186 × 208 cm	34.1 kg	Rust-resistant aluminium	Twin-wall polycarbonate	—	—	Self-assembly, 2 people, 4 to 6 hours	5-year defects and workmanship	Hinged lockable door	1 roof vent	Gutters and galvanised steel base	—	—
Palram-Canopia Mythos 6x8 Greenhouse, Silver	Palram-Canopia	£319.00	One Garden	185 × 247 × 208 cm	39.1 kg	Rust-resistant aluminium	Twin-wall polycarbonate	—	—	Self-assembly, 2 people, 4 to 6 hours	5-year defects and workmanship	Hinged door	1 opening window	—	—	—
Palram-Canopia Eco Grow 6x6 Greenhouse	Palram-Canopia	£879.00	One Garden	204 × 201 × 198 cm	54.7 kg	Green resin	—	—	—	No-tool self-assembly	7-year defects and workmanship	Hinged door	1 roof vent	—	4 mm twin-wall polycarbonate	6 mm twin-wall polycarbonate

The details

Six polycarbonate greenhouses compared

01 · Best Timber Mini Greenhouse

Rowlinson Hardwood Mini Greenhouse

A small hardwood-framed unit with twin-wall glazing, two shelves and two lifting lids, for £229.

The Rowlinson Hardwood Mini Greenhouse is the only timber model here and the smallest. It stands 144 cm tall on a 120 x 63 cm footprint, so it suits a patio or a sheltered corner rather than a walk-in plot. The frame is FSC hardwood, paired with twin-wall polycarbonate glazing. Two shelves hold pots and trays. Two lifting lids with adjustable stays let you decide how much air gets in. It weighs 30 kg and is listed at 1 to 2 hours to assemble, far quicker than the walk-in models. The wood needs a little yearly care, as annual treatment is recommended.

Price snapshot: £229.00 at One Garden, recorded 2026-11-02. Check the retailer page for the current price.

Key specifications

Dimensions: 120 × 63 × 144 cm
Weight: 30 kg
Frame: FSC hardwood
Glazing: Twin-wall polycarbonate
Shelves: 2
Lids: 2 lifting lids with adjustable stays
Assembly: Self-assembly, 1 to 2 hours
Warranty: 12-month parts

What stands out

Quick to build, with assembly listed at 1 to 2 hours
Two lifting lids with adjustable stays give flexible ventilation

Things to consider

Annual timber treatment is recommended
Only a 12-month parts warranty

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02 · Best All-Rounder

Palram-Canopia Mythos 6x4 Greenhouse, Silver

A well-equipped 6x4 walk-in with twin-wall glazing, two vents and a steel base for £289.

The Palram-Canopia Mythos 6x4 Greenhouse, Silver is the entry point to the Mythos range. Its 185 x 126 x 208 cm footprint is big enough to step inside, yet modest enough for many gardens. The rust-resistant aluminium frame carries twin-wall polycarbonate glazing. Ventilation comes from an opening window and a roof vent, and gutters are fitted too. A galvanised steel base is part of the package. At 26.5 kg it is the lightest Palram here. Two people are needed to build it, and the job is listed at 4 to 6 hours.

Price snapshot: £289.00 at One Garden, recorded 2026-11-02. Check the retailer page for the current price.

Key specifications

Dimensions: 185 × 126 × 208 cm
Weight: 26.5 kg
Frame: Rust-resistant aluminium
Glazing: Twin-wall polycarbonate
Door: Hinged single door
Ventilation: 1 opening window and 1 roof vent
Extras: Gutters and galvanised steel base
Assembly: Self-assembly, 2 people, 4 to 6 hours
Warranty: 5-year defects and workmanship

What stands out

Opening window and roof vent give two ways to ventilate
Galvanised steel base and gutters are included

Things to consider

Assembly needs two people and takes 4 to 6 hours

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03 · Best for Green Colour Styling

Palram-Canopia Hybrid 6x4 Greenhouse, Green

A green powder-coated 6x4 with a door and window, but it costs £65 more than the same-sized Mythos.

The Palram-Canopia Hybrid 6x4 Greenhouse, Green shares its 185 x 126 x 208 cm footprint with the Mythos 6x4. It uses a powder-coated aluminium frame with polycarbonate roof and wall panels. That makes it the one to look at if you want a green finish rather than silver. It has a hinged door and one opening window. It weighs 27.4 kg and, like the other Palrams, needs two people for 4 to 6 hours of assembly. The 5-year warranty covers defects and workmanship. At £354 it is the second-priciest here, and £65 more than the same-sized silver Mythos 6x4.

Price snapshot: £354.00 at One Garden, recorded 2026-11-02. Check the retailer page for the current price.

Key specifications

Dimensions: 185 × 126 × 208 cm
Weight: 27.4 kg
Frame: Powder-coated aluminium
Glazing: Polycarbonate roof and wall panels
Door: Hinged door
Ventilation: 1 opening window
Assembly: Self-assembly, 2 people, 4 to 6 hours
Warranty: 5-year defects and workmanship

What stands out

Green powder-coated frame offers a different look to the silver models
Hinged door and opening window are included

Things to consider

Costs £65 more than the same-sized Mythos 6x4
At 27.4 kg, it weighs 0.9 kg more than the Mythos 6x4

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04 · Best for Secure Mid-Size Growing

Palram-Canopia Mythos 6x6 Greenhouse, Silver

A 6x6 walk-in with a lockable door, roof vent, gutters and steel base, at £334.

The Palram-Canopia Mythos 6x6 Greenhouse, Silver gives you 186 cm of length, which is 60 cm more than the 6x4. The rust-resistant aluminium frame holds twin-wall polycarbonate glazing, and the hinged door can be locked. Airflow comes from a roof vent, and gutters and a galvanised steel base come with it. At 34.1 kg it is heavier than the 6x4 but lighter than the 6x8. Assembly needs two people for 4 to 6 hours, and the 5-year defects and workmanship warranty applies. It costs £15 more than the longer 6x8.

Price snapshot: £334.00 at One Garden, recorded 2026-11-02. Check the retailer page for the current price.

Key specifications

Dimensions: 185 × 186 × 208 cm
Weight: 34.1 kg
Frame: Rust-resistant aluminium
Glazing: Twin-wall polycarbonate
Door: Hinged lockable door
Ventilation: 1 roof vent
Extras: Gutters and galvanised steel base
Assembly: Self-assembly, 2 people, 4 to 6 hours
Warranty: 5-year defects and workmanship

What stands out

Lockable hinged door adds some security
Roof vent, gutters and galvanised steel base are all included

Things to consider

Costs £15 more than the larger Mythos 6x8
Ventilation comes from one roof vent

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05 · Best for Floor Space on a Budget

Palram-Canopia Mythos 6x8 Greenhouse, Silver

The longest model here at 247 cm, with a door and window, for £319.

The Palram-Canopia Mythos 6x8 Greenhouse, Silver has the largest footprint of the six at 185 x 247 cm. It still costs less than the 6x6, at £319. You get a rust-resistant aluminium frame with twin-wall polycarbonate glazing, a hinged door and one opening window. The 6x4 and 6x6 also include a roof vent, gutters and a galvanised steel base, while this model gives you the most floor length. It is also the heaviest of the Mythos range at 39.1 kg. Two people are needed for assembly, listed at 4 to 6 hours. The 5-year defects and workmanship warranty is the same as on the other Mythos models.

Price snapshot: £319.00 at One Garden, recorded 2026-11-02. Check the retailer page for the current price.

Key specifications

Dimensions: 185 × 247 × 208 cm
Weight: 39.1 kg
Frame: Rust-resistant aluminium
Glazing: Twin-wall polycarbonate
Door: Hinged door
Ventilation: 1 opening window
Assembly: Self-assembly, 2 people, 4 to 6 hours
Warranty: 5-year defects and workmanship

What stands out

Largest footprint of the six at 185 x 247 cm
£15 cheaper than the smaller Mythos 6x6

Things to consider

Costs £30 more than the same-sized Mythos 6x4
Heaviest Mythos model here at 39.1 kg

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06 · Best Premium Resin Walk-In

Palram-Canopia Eco Grow 6x6 Greenhouse

A resin-framed 6x6 with thicker side panels and no-tool assembly, but it costs £879.

The Palram-Canopia Eco Grow 6x6 Greenhouse is the only resin model and the most expensive by a wide margin. It stands 198 cm tall on a 204 x 201 cm footprint, so it is wider and deeper than the Mythos 6x6 but not as tall. The roof uses 4 mm twin-wall polycarbonate panels, and the sides use thicker 6 mm panels. A hinged door gives access and a roof vent handles airflow. Assembly is no-tool, which sets it apart from the other models here. It weighs 54.7 kg, the heaviest of all six. The warranty runs for 7 years against defects and workmanship.

Price snapshot: £879.00 at One Garden, recorded 2026-11-02. Check the retailer page for the current price.

Key specifications

Dimensions: 204 × 201 × 198 cm
Weight: 54.7 kg
Frame: Green resin
Roof glazing: 4 mm twin-wall polycarbonate
Wall glazing: 6 mm twin-wall polycarbonate
Door: Hinged door
Ventilation: 1 roof vent
Assembly: No-tool self-assembly
Warranty: 7-year defects and workmanship

What stands out

No-tool assembly needs no screwdriver or spanner
6 mm side panels are thicker than the 4 mm roof panels

Things to consider

£879 is more than double the price of any other model here
Heaviest of the six at 54.7 kg

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