About Our Cold Frames and Mini Greenhouses
We stock 34 cold frames, mini greenhouses, and growhouses from three trusted manufacturers. Access cold frames make up the bulk of the range, from compact 1x3 lean-to models to the 3x6 Exbury freestanding unit. Elite cold frames offer the Min E Lite series in 4x2, 6x2, and 8x2 sizes, plus the Window Garden greenhouse for wall mounting. Palram Canopia provides the budget-friendly Ivy growhouse and the raised Plant Inn cold frame.
Every model uses rust-proof aluminium framing with your choice of 3mm toughened safety glass or twin-wall polycarbonate glazing. Prices range from £249 for the Elite Min E Lite 4x2 to £1,275 for the 3x6 Access Exbury. All orders include free UK mainland delivery.
Cold frames sit directly on the ground and trap solar warmth to extend your growing season by 6-8 weeks. They are essential for hardening off seedlings, overwintering tender plants, and growing salad crops from October through March. For taller plants or vertical growing, browse our mini greenhouses or full-size greenhouses.
Why We Chose This Range
"We test every cold frame before we list it. The most common failure we see is lightweight plastic units that crack in UV and blow over in spring gales. That is why we only stock aluminium-framed models from Access and Elite. They use the same extruded aluminium profiles and 3mm toughened glass as full-size greenhouses. The Access Exbury and the Elite Min E Lite both include floor-fixing brackets as standard. A cold frame acts like a wing in high wind. Without proper anchoring, your first March gale sends it across the garden."
— Matt, Founder of Greenhouse StoresTypes of Cold Frame We Offer
Traditional Cold Frames
Low-profile aluminium frames with hinged glass lids. Sit directly on soil or paving. The Access 4x4, 6x4, and 8x4 models hold 12 to 70+ seed trays. Ideal for hardening off and overwintering.
Mini Lean-To Greenhouses
Taller units that lean against a house or garage wall. The Access Westminster and Harlow ranges fit into spaces as narrow as 1ft deep. Use the wall's stored heat for an extra 2-3°C overnight.
Freestanding Growhouses
Walk-around mini greenhouses with shelving on both sides. The Access Exbury and Midi ranges provide serious growing space in a 2ft to 3ft footprint. Toughened glass on all sides.
Growhouses on Wheels
The Access wheeled growhouse rolls into position for the growing season and stores flat against a wall in winter. Lockable castors. Available in 2x3 standard and 2x3 midi sizes.
Sizing guide: A 4x2 cold frame holds 12-16 seed trays. A 4x4 holds 30-35 trays and is the UK's most popular size. An 8x4 holds 70+ trays for serious propagation. Measure your available ground space and pick the largest model that fits.
Matt's Installation Tip: The Thermal Mass Strategy
Place your cold frame on a bed of 50mm dark paving slabs or slate chippings rather than bare soil. Dark stone absorbs solar heat during the day and radiates it back to your plants overnight. This simple step raises the minimum temperature inside the frame by 2-3°C on frosty nights.
The base must be perfectly level. Even a 5mm twist causes the roof vents to misalign, leaving gaps that let frost in. Position the frame against a south-facing wall if possible. The wall's stored heat boosts overnight temperatures by another 20%. Read our full base preparation guide here.
Aluminium vs Timber vs Plastic Cold Frames
| Feature | Aluminium (our range) | Timber | Plastic |
|---|---|---|---|
| Lifespan | 25+ years | 10-15 years | 3-5 years |
| Maintenance | Zero — wipe clean | Annual oil or stain | None (but degrades) |
| Glazing | 3mm toughened glass | 3mm toughened glass | Thin polycarbonate sheet |
| Wind resistance | High — floor-fixing brackets | Medium — heavy but no anchoring | Low — blows over easily |
| Light transmission | 92% (glass) | 92% (glass) | 70-80% |
| Insulation | Good | Best — natural thermal break | Poor |
| Typical price | £249-£1,275 | £150-£400 | £30-£80 |
Frequently Asked Questions
What is the difference between a cold frame and a mini greenhouse?
A cold frame sits on the ground with a hinged lid. It is low-profile and designed for hardening off seedlings, overwintering plants, and growing low crops like salad leaves. A mini greenhouse stands upright with shelving, making it better for vertical growing on patios and balconies.
Is toughened glass or polycarbonate better for a cold frame?
Toughened glass gives 92% light transmission and stays clear for decades. Polycarbonate offers 20% better insulation and is virtually unbreakable, making it safer for gardens with children or pets. Glass is heavier, which helps anchor the frame in wind. Most of our customers choose glass.
How do I stop plants overheating in a cold frame?
Open the roof vents every morning on sunny days from March onwards. Temperatures inside a closed cold frame spike to 35°C+ on a bright spring afternoon. Prop the lid 10-15cm with a block of wood, or fit an automatic vent opener that reacts to temperature changes while you are at work.
What size cold frame do I need?
A 4x4 cold frame is the most popular UK size. It holds 30-35 standard seed trays and suits most gardeners. A 4x2 holds 12-16 trays for smaller gardens. The 8x4 Access model holds 70+ trays and is the choice for serious propagators and allotment growers.
Can I use a cold frame all year round?
Yes, aluminium cold frames are designed for permanent outdoor use. In spring, use them to harden off seedlings. In summer, grow melons, peppers, and aubergines. In autumn, extend the salad season into November. In winter, protect alpines and overwintering plants from excessive rain and frost.
Do I need a base for a cold frame?
A level, hard surface gives the best results. Paving slabs, compacted gravel, or a concrete pad all work. Avoid placing a cold frame directly on soil, which is rarely level and causes the frame to twist. Dark paving absorbs heat during the day and releases it overnight, keeping the interior 2-3°C warmer.
How much does a cold frame cost?
Our aluminium cold frames start from £249. Traditional flat cold frames range from £249 to £659 depending on size. Mini lean-to greenhouses cost £324 to £949. Freestanding growhouses range from £425 to £1,275. All prices include free UK mainland delivery and a manufacturer warranty.
Need Help Choosing?
Call our team free on 0800 098 8877. We will help you pick the right size, glazing, and style for your garden.