The best cold frames, compared.
Top pick: Outsunny fir cold frame – Strongest review line in this set, 4.3 from 271, at about £46.99 with an agreed 100 × 65 × 40 cm size. Best value: Outsunny twin-lid cold frame – Two lids for staged venting at about £47.59, in the same entry price band as the top pick. Updated October 2026.
A cold frame is a low glazed box for hardening off seedlings and giving them more frost shelter than a cloche. You want one when a walk-in greenhouse will not fit and a tray of plants still needs a lid you can prop open. The Royal Horticultural Society treats ventilation as essential and says lightweight frames need pegging down in wind. They are not a promise against a hard frost. What separates them is whether the lid vents, whether the timber survives damp soil, and whether doors on a taller cabinet actually meet. The [cold frame buying guide](/hub/raised-beds-greenhouses-and-compost/cold-frame/sub/cold-frame-buying-guide) sets footprint, glazing and lid type before the table. You use it to harden off seedlings, extend the season, and give more frost shelter than a cloche. The Royal Horticultural Society puts plants in a cold frame with the lid slightly open by day and closed at night for about two weeks before planting out.
A cold frame is a low glazed box for hardening off seedlings and giving them more frost shelter than a cloche. You want one when a walk-in greenhouse will not fit and a tray of plants still needs a lid you can prop open.
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Personal buying guide
Question 1 of 2
What shape do you need?
The Outsunny 845-471 is a low fir-and-polycarbonate cold frame at £46.99, with 4.3 from 271 amazon.co.uk reviews, the strongest star line in this six-item set. Title and technical rows agree on 100 × 65 × 40 cm, the pack weighs 4.4 kg, and the listing shows one top opening with polycarbonate as the cover. Reviewers often call it good value, large enough for a useful number of plants, and well made for a patio. Some mention transit damage, and several say the wood wants a coat before winter. At about 40 cm high it is a tray-level frame, not a shelved cabinet you stand beside. That is the strongest review line in this set, which is why this listing is the top pick. Leave it if you need two lids you can open separately, or a door at standing height.
Pros
Cons
Best for: You are hardening off on a patio or paving and want the strongest review line in this set under £50.
Less suitable: You need a twin lid, standing height, or timber you will not treat before winter.
Specifications
Common questions
Does the listing state polycarbonate?
The listing names polycarbonate as the cover, on a fir frame, with one top opening.
What footprint is listed?
The title and the technical row both say 100 × 65 × 40 cm. The pack weight is 4.4 kg.
What do UK reviews repeat?
A coat of preservative on the fir before winter, and occasional transit damage.
The SG Traders wooden greenhouse is a tall cabinet at £79.99, with 4.2 from 220 amazon.co.uk reviews. The technical row is 69 × 49 × 120 cm and the title says 120 h × 69 w × 49 d, so the long dimension is height, not a knee-high lid. Polycarbonate panels, a wooden frame, 7 kg, two doors and four vents are listed, and the title mentions removable shelves. Reviewers often call it a useful small greenhouse and mention straightforward assembly. Opacity comes up often enough that some people alter a door so they can see inside. It matches the low Outsunny frames on stars, not on shape: you need headroom and a path to the doors. It is the mid-price tall option here, above the 3.2-star three-tier and below the £129.99 planter frame.
Pros
Cons
Best for: You want shelves and standing access in a wooden polycarbonate cabinet around £80.
Less suitable: You need a clear view through the panels, or a low lid over seed trays on the ground.
Specifications
Common questions
Does the listing state polycarbonate?
The listing names polycarbonate panels on a wooden frame, with two doors and four vents.
What footprint is listed?
The technical row says 69 × 49 × 120 cm. The title says 120 h × 69 w × 49 d, so the long dimension is height.
What do UK reviews repeat?
Panels described as opaque, with some buyers altering a door so they can see inside.
The feel good planter-style frame is the dearest listing in this set at £129.99, with 4.2 from 146 amazon.co.uk reviews. The title reads 120 h × 30 d × 100 w, and the item-dimensions field is not filled in the raw file, so height and depth are not a settled pair of numbers. The cover row names polyvinyl chloride, the frame is wood, and the pack weighs 16.2 kg, the heaviest here. Positive UK reviews call the finished box attractive and suitable for small garden crops, and some buyers say it was better than they expected. The same reviews repeat poor instructions, timber that needs pretreatment, and a price that feels high for the build, including complaints after a Prime price drop. A 4.2 at this price is not a specialist aluminium-and-glass frame, which often sits above £200 outside this capture. Read the centimetre line before you pay the top price in the set.
Pros
Cons
Best for: You want a long wooden planter-style frame and will pretreat the timber and work from thin instructions.
Less suitable: You need one clear centimetre row, polycarbonate named as the cover, or a kit under £80.
Specifications
Common questions
Does the listing state polycarbonate?
The cover row names polyvinyl chloride. Polycarbonate is not the material on that row.
What footprint is listed?
The title says 120 h × 30 d × 100 w. The item-dimensions field is empty, so height and depth are not a settled pair.
What do UK reviews repeat?
Poor instructions, timber that needs pretreatment, and a price that feels high for the build.
The Spear & Jackson COLDFRAME1 is a low single-lid kit at £68.94 on amazon.co.uk, with 4.0 from 172 reviews in the 20 October 2026 capture. The technical row lists 90 × 45 × 46 cm and 3.3 kg, while a title bullet still says 1000 × 660 × 400 mm, so those are two size lines rather than one footprint you can mark out on the patio. The cover row says plastic panes and the frame row says plastic, even though the marketing talks about timber. UK reviews often praise one-person assembly, predrilled holes on one side, and a box that feels sturdy once the corner brackets are fitted, and some mention fast delivery. The same reviews return to soft wood that needs treatment each year, a price that feels high for the material, and lid props that are stiff and sit on the outside rather than where the photo suggests. Paint blistering on the metal props is another repeated complaint. It carries no award in this set.
Pros
Cons
Best for: You want a named low single-lid frame and will check both size lines before you order.
Less suitable: You need one agreed footprint, or you want the wider fir-and-polycarbonate frame at £46.99.
Specifications
Common questions
Does the listing state polycarbonate?
The cover row names plastic panes. The frame row says plastic, while the marketing talks about timber.
What footprint is listed?
The technical row says 90 × 45 × 46 cm. A title bullet says 1000 × 660 × 400 mm. Those are two size lines.
What do UK reviews repeat?
Soft wood that needs treatment each year, stiff lid props mounted on the outside, and paint blistering on the metal props.
The Outsunny 845-538ND is the twin-lid fir frame at £47.59, with 4.0 from 121 amazon.co.uk reviews. Title and item rows both read 100 × 50 × 36 cm, so it is narrower and slightly lower than the 100 × 65 × 40 cm single-lid Outsunny. Two top covers and two vents are listed, and the pack weighs 8 kg, against 4.4 kg for that single-lid kit. UK reviews say the size is reasonable once it is built, and they also repeat recoating before use, fixes during construction, and a share of comments that it is not very good. It sits in the same entry price band as the top pick without matching 4.3 from 271. It is the best value here because the twin lids allow staged venting at £47.59, not because the reviews are the strongest. At 36 cm high it will not take tall pots.
Pros
Cons
Best for: You want two lids you can open separately and will treat the fir before it stays outside.
Less suitable: You want the wider 65 cm single lid, or you are choosing on star count alone.
Specifications
Common questions
Does the listing state polycarbonate?
The listing names polycarbonate as the cover, on a fir frame, with two top covers.
What footprint is listed?
The title and the technical row both say 100 × 50 × 36 cm. The pack weight is 8 kg.
What do UK reviews repeat?
Recoating before use, fixes during construction, and a share of comments that it is not very good.
The Outsunny three-tier, model UK845-0440331, is listed at £56.99 with 3.2 from 201 amazon.co.uk reviews, the weakest star line in this set. The technical row gives 58 × 44 × 78 cm, fir wood, polycarbonate, 7.5 kg, two doors and two vents. A minority of UK reviews say the small cabinet works, and the shelf price is below the SG Traders unit at £79.99. Far more reviews describe doors that do not meet, warped boards, fiddly assembly and poor value. That review line, rather than the low price alone, is why it sits last in this set. It is a compact tall kit only if the doors happen to close, not a stand-in for the 4.3-star low frame at £46.99. Skip it when a flush door matters more than saving about £23 against the taller SG Traders cabinet.
Pros
Cons
Best for: You have a tight corner, will assemble carefully, and can live with doors that may not meet.
Less suitable: You want doors that close flush, or the strongest review line in this set.
Specifications
Common questions
Does the listing state polycarbonate?
The listing names polycarbonate on a fir frame, with two doors and two vents.
What footprint is listed?
The technical row says 58 × 44 × 78 cm. The title describes a three-tier cabinet rather than a second centimetre line.
What do UK reviews repeat?
Doors that do not meet, warped boards, and fiddly assembly.
Six cold frames and tall wooden cabinets on amazon.co.uk were scored from listing lines captured on 20 October 2026 and from saved review signals. There was no lab frost test and no assembly trial. Weights sum to 100: Amazon evidence 40, fit for hardening off and venting 35, and value 25. The highest total is the top pick. The twin-lid frame is the best value because two lids vent in stages near the same shelf price.
Amazon evidence
40%The amazon.co.uk star line and review count for that ASIN, including whether UK reviews repeat warped boards, doors that do not meet, or timber that needs treatment. The figure is a scaled shelf signal, not a lab score.
Fit for hardening off and venting
35%Whether the lid vents, the height suits trays rather than a shelved cabinet, and the listed size lines agree. A low frame with a prop-open lid scores above a tall cabinet whose doors UK reviews say do not meet.
Value
25%Shelf price in GBP against a usable lid and a review line that supports it. A lower price does not carry the row when doors do not meet. The twin-lid frame scores here on staged venting near £47.
Match the shape to the job before you compare stars. A knee-high lid hardens off trays. A 120 cm cabinet is a mini-greenhouse and needs headroom. Polycarbonate and other plastic glazing are what these six listings actually state. Timber at soil level wants preservative, whatever the title photo suggests. Prices below are shelf lines from 20 October 2026, and about £130 is the top of this set. Aluminium-and-glass frames from garden retailers often sit above £200.
A cold frame is a low, glazed box, usually timber or aluminium with glass or polycarbonate lids, that sits on soil, gravel or paving. You use it to harden off seedlings, extend the season, and give more frost shelter than a cloche. The Royal Horticultural Society puts plants in a cold frame with the lid slightly open by day and closed at night for about two weeks before planting out. A cloche gives less frost protection than a cold frame. These unheated boxes moderate temperature.
The SG Traders unit is 120 cm high and the three-tier is 78 cm. Both need a path to the doors. A cold frame for trays on the ground is the 36 to 46 cm group. Read the height before you order from a photo that says cold frame.
UK reviews of the fir frames and the Spear & Jackson kit return to wood that needs preservative before winter, or each year. Damp soil at the base rots untreated timber faster. A painted or natural finish in the title is not a five-winter record.
The Royal Horticultural Society treats ventilation as essential. A closed lid on a warm day cooks seedlings. Lightweight frames also need pegging in wind. These boxes moderate frost. They do not state a temperature they will hold.
Footprint and height decide whether the kit is a cold frame or a shelved cabinet. A true cold frame is roughly knee height, with a sloping lid over about one tray of plants. The Outsunny fir frame is 100 × 65 × 40 cm and the twin-lid frame is 100 × 50 × 36 cm. The Spear & Jackson technical row says 90 × 45 × 46 cm, while a title bullet still says 1000 × 660 × 400 mm, so mark the patio only after you know which line you are buying.
Every listing in this set is plastic glazing. Polycarbonate passes less light than glass, and it is lighter and cheaper. Do not treat a glass look in a title photo as horticultural glass. None of these six claims toughened glass. The Outsunny frames and the SG Traders cabinet name polycarbonate. The Spear & Jackson cover row says plastic panes, and the frame row says plastic, even though the marketing talks about timber. The FeelGoodUK cover row names polyvinyl chloride.
Three typical situations, each with a recommendation from this comparison.
You are moving trays outside for about two weeks and you need a low lid you can prop, plus pegs in wind. The Outsunny fir cold frame is the top pick at about £46.99, 100 × 65 × 40 cm, with 4.3 from 271 reviews. Leave it if you need two lids or standing height.
You want staged venting near the top pick on price, and you will treat the fir before winter. The Outsunny twin-lid cold frame is the best value at about £47.59. It is 36 cm high, so tall pots will not fit, and UK reviews mention recoating and fixes during construction.
You want standing access and shelves rather than a lid over trays on the ground. The SG Traders wooden greenhouse is about £79.99 and 120 cm high, with 4.2 from 220 reviews. Leave it if the panels must be clear. The cheaper three-tier often has doors that do not meet.
Inside these six amazon.co.uk listings, the Outsunny fir cold frame is the top pick: about £46.99, 100 × 65 × 40 cm, polycarbonate on fir, and 4.3 from 271 reviews. The fir still wants a coat before winter. The Outsunny twin-lid frame is the best value at about £47.59, because two lids vent in stages near that price. The SG Traders cabinet is the tall option at about £79.99 if you need shelves. The three-tier is cheaper, and many UK reviews say the doors do not meet. The FeelGoodUK frame is the dearest row, and its centimetre line is not settled.
Outsunny fir cold frame
Strongest review line in this set, 4.3 from 271, at about £46.99 with an agreed 100 × 65 × 40 cm size.
Outsunny twin-lid cold frame
Two lids for staged venting at about £47.59, in the same entry price band as the top pick.
Editorial
Peter F. is the editor for DIY & tools at productscompared.co.uk. Comparisons in this category are checked against amazon.co.uk listings, review evidence and public UK sources.
Guides on what to look for, how to use a product, and common mistakes.
Public UK sources from the research digest, last checked on 20 October 2026. Amazon.co.uk listing lines are the price and review source for the six ASINs. No frost or assembly test was run.
This article contains affiliate links. If you buy through these links, we may earn a commission at no extra cost to you. The cards use amazon.co.uk listing data and public UK sources. They are not a laboratory test.
