Thinking of getting a greenhouse or cold frame. Advice needed please

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Trevk81
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Thinking of getting a greenhouse or cold frame. Advice needed please

Post by Trevk81 »

My collection is quickly outstripping windowsill capacity and I think I need to get some more space outside. I was thinking that a cold frame might be a way to dip a toe in outside storage but also tempted to go for it and get a greenhouse.

Any advice is welcome, I’m concerned about needing to heat it etc. Would a start be only using it for cacti and succulents that are hardy to UK winters?
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Re: Thinking of getting a greenhouse or cold frame. Advice needed please

Post by Aiko »

There are many cacti (and some succulents) that can easily tolerate winter frost. So getting an unheated cold frame or (better) greenhouse and start filling it up with hardy Pediocactus, Escobaria, Echinocereus (most species anyway). There are quite some Gymnocalyciums and Mammillaria that are very hardy too.

But most cacti can also easily tolerate -5C top -10C on occasional nights. If frost is severe and prolonged, you can always carry the plants inside for a few nights that cannot tolerate colder than -10C. How often do you get those temperatures where you live? Up here only a few nights in a row once every few years.
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Re: Thinking of getting a greenhouse or cold frame. Advice needed please

Post by Davey246 »

Decide what you want to or could spend, that will go a long way to making the decision for you.

Buy second-hand - if you are patient, you may get one free as many people move house and gain a greenhouse that they do not want, so offer them free to anyone who will dismantle and remove. Coldframes are easily broken-down and disposed of, so are not so common on Freecycle and the likes.

Coldframes - not ideal as they are at ground-level (although they can be raised, on legs) and ground level-means problems with slugs and snails, sometimes mice, and usually damp.

A greenhouse can provide at least 3 levels of space for plants - you can cram an awful lot in. One of my greenhouses even has sliding shelving that pushes under the bench on one side so when I am not in it, the entire space can be filled with plants, filling what was the walkway.
Trevk81
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Re: Thinking of getting a greenhouse or cold frame. Advice needed please

Post by Trevk81 »

That’s good to know that most are hardy and you’re right I don’t think many nights especially in row go below -5. I take it people heat them for seed growing? Not really a priority at the minute, I just need more space.

Thats clever that the draws can slide making use of the space. I’m making note of that!

Good advice about 2nd hand, and setting a budget. This is start of an ever increasing cycle of buying bigger and bigger greenhouses isn’t it?! haha
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Re: Thinking of getting a greenhouse or cold frame. Advice needed please

Post by Davey246 »

Heating to around 5C just means that very, very few cacti, though far more succulents, can't be kept outdoors. 10C would cost a fortune but enable virtually any C&S to get by outdoors. Seed-raising generally, really requires something like 20C, or above for some species - lots of exceptions though.

How big can your garden cope with?
There is one thing for certain that all keen gardeners agree on - the greenhouse you've just bought is too small!!!

Even so, using staging and shevles, you'll get a lot in, but the access path/corridor generally needs to be the same - around 2 feet wide, so smaller greenhouses lose proportionally more space (unless you fit sliding benches).

Any less hardy plants can be selectively kept warmer than the rest by using some kind of seperately heated coldframe within the main greenhouse, which would not break the bank in fuel costs. (Another thing to bear in mind - errect whatever you get within easy distance of power, even if via an extension lead.)

One thing to avoid if you are thinking at least several years, or more - plastic, any part.
Trevk81
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Re: Thinking of getting a greenhouse or cold frame. Advice needed please

Post by Trevk81 »

Yeah I’ve seen on reviews of greenhouses people complaining about plastic window mechanisms failing not long after buying.

Right then I need to keep an eye out for a second hand greenhouse slightly bigger than I need and double check the hardiness of my collection!

Thank you for all the advice :)
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Re: Thinking of getting a greenhouse or cold frame. Advice needed please

Post by Davey246 »

The other thing to bear in mind is that a few succulents do better out of full sun - in my experience Gasteria and Sansevieria do better in very light shade than they do in full sun,for instance. The same goes for some of the bulbs grown by C&S enthusiasts.

I've not come across any cacti that I could say the same of, although quite a few will easily scorch if dry or very dry while the weather is hot/bright.

Which brings another point - unless you want to tempt fate (you'll lose at some time), you MUST have at least one roof vent in a greenhouse, and fit an auto-opener. Most makers of greenhouses offer vents of all kinds as after-market options, so if buying second-hand, check the brand. If you want to use the door as well, for ventilation, you'll also need some kind of simple rigid mesh to fit the gap or whole door opening - there is nothing so tempting to cats as a very cosy, very warm and sunny spot, out of any breeze, in which to snooze.
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Re: Thinking of getting a greenhouse or cold frame. Advice needed please

Post by Paul in Essex »

Just recently Gumtree in Essex has had several free greenhouses listed. I'm sure most areas would be the same. You have to dismantle them generally but that is a good thing to learn anyway, taking pics as you go. and armed with a can or 2 of WD40 or other penetrating oil :)

I think if I were in your position, pretty much startingd from scratch, I'd be looking at plants that will be ok in an unheated greenhouse. As soon as you start heating Life becomes incredibly more complex. Heating costs this coming winter will be astronomical, so not heating your space at all will seem even more attractive. Plus the cost of the heater, the thermostat, installing power etc etc.

There are literally hudreds and hundreds of cacti and other succulents that can be grown in unheated glass, kept dry, and you can easily build up a varied and interesting collection from a cold start (! :) ) in this way. It is only really if you start off with or develop a particular interest in frost intolerant plants that heating becomes a requirement.
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Re: Thinking of getting a greenhouse or cold frame. Advice needed please

Post by Davey246 »

Largely agreed, but a heater and thermostat can cost relative peanuts - mine cost very litttle, although I did build the thermostats.
There is also the fact that @Trevk21 is looking to house an exisiting collection rather than looking to extend the collection by sticking with hardy species. If the tender species won't overflow window-boards, all will be well.

Fuel costs are another matter entirely.

Corroded aluminium nuts and bolts are not worth the cost of WD40 - sheer them off and buy new. Been there, done that - two glasshouses, two house moves.
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Re: Thinking of getting a greenhouse or cold frame. Advice needed please

Post by Al Laius »

An actual example of ‘heater for peanuts’ would be useful rather than just the statement itself. I’m in the market for a couple if you know where I can get some.
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Davey246 wrote: Sat Jun 04, 2022 8:31 pm Largely agreed, but a heater and thermostat can cost relative peanuts - mine cost very litttle, although I did build the thermostats.
There is also the fact that @Trevk21 is looking to house an exisiting collection rather than looking to extend the collection by sticking with hardy species. If the tender species won't overflow window-boards, all will be well.

Fuel costs are another matter entirely.

Corroded aluminium nuts and bolts are not worth the cost of WD40 - sheer them off and buy new. Been there, done that - two glasshouses, two house moves.
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