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Last year I overwintered plug plants in a plastic greenhouse which I moved into the garage for extra frost protection.

OH says he is not happy to have plants in the garage as there is insufficient ventilation, causing condensation and consequent damage. I can't argue with that so I need a solution please.

I quite like the little glass and wood 'grow houses'.

But would a grow house be warm enough, when/why would I need a heater? When would I need to open/close the windows?

I don't want to spend too much (but birthday coming up), also bubble wrapping the inside of the plastic thing sounds fiddly.

I assume it will be too warm in the house (no consevatory).

I don't have a suitable site against a house/warm wall but have sheltered areas under trees.

I'm not sure when to use various products ; cold frame, greenhouse, cloche, fleece.

Please help me decide what to do and what to buy to protect the following plants.


2.allium hairy green (that's whats on the label!)

3. evening primrose

4.salvia hot lips

5.salvia patio deep blue .... I think this one is too tender for outside???

6. penstemon garnet

7.cerinthe kiwi blue (2"high with 4 stems, quite healthy at the moment, seed sown wrong time of year I think)???

8.eryngium (may already have been eaten by slugs or gone to sleep for winter,I can't tell which)

9. alstromeria psittacina 'Royal Star' --- This is my favourite, there have been no side shoots (only leaves) to take cuttings, the seeds don't seem to be drying out (still green). It has started to die back. it's in the ground so I was hoping to use a cloche bell but no idea really.



I've got a wooden 'growhouse' very similar to this one  got it from Notcutts and it's quite sturdy.  I over-winter plugs and cuttings of hardy perennials in it, and sweet pea seedlings.  I have the lid propped open quite a bit most of the day and only shutting it on frosty nights. 

When it was very very cold last winter I popped a layer of the 'big bubble' bubblewrap around things that I thought were a little more tender at night time, again removing it during the day.  

I would've thought a garage would be too dark for plugs and cuttings. 

Hello MrsG, Yes, I'd say it's too cold round here for your salvias to survive the winter. At least, I haven't managed to do it yet.

The others all need to have the frost kept at bay, also the damp, and a bit of ventilation. So you need something with an openable window at the top, ideally, so that dry and sunny weather can mop up the dampness.

And you need it big enough to house all your plants plus have enough space for a small heater for night time and other very cold spells. The earth gets colder than the air, so plants kept off the earth will be a tiny bit warmer than those on the ground. A growhouse would do that for you, but might be a bit small as you seem to have a lot of plants (lucky thing!) and I think they are a bit on the pricey side?

Maybe push for a really nice birthday present with the promise that no plants will make  the garage foggy.


Thanks Dove,

I thought you had a grow house from previous posts, it's the same one that I have put on my birthday list. My garage has plenty of light as we have replaced the original single back door with a double full glass patio door, at the time for access of equipment.( I used to put a curtain over to hide the contents but dont bother any more.)

Thanks Woody,

Salvia hot lips overwintered last year in the ground no problem but stressful!

You have me thinking again, maybe OH is right and I need him to make me one which I can fill brim full! So I've been out with tapemeasure in hand  and will ask for

length 6' depth 2' (can be deeper but will cut out light?) height 5', --- 3 slatted shelves, the bottom one in 3 pieces so I can fit a heater between, all removable and adjustable heights, ---- double glazed panels (need advice) --- window to open at top with adjusters, front opening doors (any suggestions to help retain space in front of greenhouse? ' sliding doors etc?)

Will post greenhouse design on new thread

Still not sure which plants to do what with, can some of them stay outside?



waterbutts - sorry I replied to woody by mistake. Thank you please see above!


Salvia patio blue,,echinacea and hot lips need to be protected where you are.  Hot lips is very easy from cuttings even now.  Take side shoots 3" or more long.  You will have full size flowerimg plants next summer.

If your garage has good light and is frost free you can overwimter most everything.

Just let cerinthe "tick over" in GH or that garage over winter.  Apart from patio blue a coldframe with fleece available during cold spells will be fine.  


Thanks Verdun, you think the alstromeria will be ok then?

Hiya MrsGarden.   Of course, down here so much is safe from the winter's worst  But alstromerias my experience.....suffer most in early spring when new shoots can be hit by frosts.  So I would not cover yet but have your bell cloche handy for that time.  Under the ground those fragile roots are fairly well protected so just be aware when growth re starts in spring


Hiya Mrs Garden

That growhouse is wha I was going to have for my birthday

Hope this helps but we went into a Wyevale GC yesterday and they were selling them at £69.99 - real bargain I thought

That's written only memory Verdun, thanks, very interesting too.
Bit far from me Matty, some not too much more on eBay and still may get one but thinking I might go large.not too long to vo before OH makes his informed decision.

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