Thursday 8 November 2012

My new coldframe

One of the things I bought with my £500 prize from the Achica blog competition was a coldframe. My previous one was made of aluminium with glass panels and I wasn't happy with that from a safety point of view, now that we have two grandchildren who are likely to be zooming around the garden from time to time, so I have disposed of it. The new one has a wooden frame with twin-wall polycarbonate panels, so it is a lot safer .

A coldframe is useful for two purposes: it is primarily used in the Spring-time as a place to protect tender young seedlings before they are ready for planting out, but it is also useful as a place to over-Winter potted small plants, such as herbs. A coldframe will protect your plants from the wind, and from direct contact with snow and frost, but you mustn't expect it to keep them warm. The temperature inside the coldframe in Winter is not likely to be significantly warmer than outside - perhaps a degree or so if you're lucky. I have heard though that you can create what is in effect a storage heater for your coldframe by putting inside it a large container of water (for example a 20-litre plastic jerrican). This will absorb heat from the sun during the daytime (even in Winter you usually get some sunshine most days), and will release it slowly during the night - water will cool much more slowly than the surrounding air. If you use this method, remember not to fill the container completely because if it freezes it may burst, since the volume of water increases when it becomes ice. [Note: I have not personally tried this technique. If you have, can you please let me know if it was successful?]

The new coldframe is made by Botanico. Its dimensions are 100 x 65 x 45cm. Assembly was a simple enough job, requiring only a screwdriver. Fortunately the polycarbonate glazing was already fitted in the panels.

I was unimpressed with the quality of workmanship. One of the panels was already split:

I am worried by the lightness of this product's construction. I think it may be too light, and it seems likely to be blown away at the first hint of a storm. When you buy a thing like this they always tell you its dimensions, but how often do they tell you its weight?? The wood used on this one seems exceptionally flimsy. I had been hoping for hardwood, but instead got very soft softwood - hardly more substantial than balsa! Anyway, half an hour or so later, the thing was built:

I have moved it round to the back of the house, to the place where its predecessor used to sit, and here it is duly filled with potted herbs:

At least it has a strut for propping the lid open, which will be useful (though even that is held in place by one solitary screw).

My verdict: not a quality product, but certainly has the virtue of being lightweight if that's what you are after!

List price is a whopping £79.99, but you can find it offered for about £45 if you shop around.


  1. I think if I ever made a cold frame it would be built against the foundation of the house for added heat. Also it gets the best sun in the cold months. My regular garden is shaded in the winter by the neighbors' houses.

  2. I'm trying to encourage Martyn to consider a new style cold frame but from what you say maybe not this one.

    Could you somehow fasten it to something solid?

  3. Congratulations on the blog prize dude! I love my coldframe, it's really useful. Luckily my husband is rather handy with woodwork but even good softwood can shrink and we have a few gaps. He is devastated but it's not a reflection of his handywork, which is great. I hope to post the dimensions/designs up for it soon. We re-used some old sliding windows, reminds me of getting an ice-cream out of one of those freezers every time I go in it!
    Anna B

  4. It looks rather nice! I hope it's long lasting. Hard to know how long products with last nowadays.

  5. I like the strut for keeping it open. I think that would be better for sunlight and air. Hopefully it will hold up to some winds. :/

  6. look at you go!... i've got some old windows at home, I may try making something a little like this with those... i'll let you know how it goes!

  7. Well....I don't have a cold frame so if it was mine, I would probably love it (little or no wind here) but I haven't found a window that I can use and I wouldn't buy something that can be so easily built (because I can't afford to, I'm sure I would if I could afford it). I'll have to keep waiting until I find a window and some wood is given to us, sigh. It really doesn't look too bad though and I like that it is clear on the sides as well as the top.

  8. Interesting post. I've always wanted a cold frame but not quite sure what I'd put in it. Shame about the split panel.

  9. Sorry about the quality issue... Interested in how it works....


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