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Using a propogater as a cold frame?

Hello there, new to the forum ( and gardening) hope this is the right area to post.

hope you are all well

In early february I sewed some sweet peas, left them to germinate on a window cill.

they've been there ever since and are doing very well - my worry being they'll sucomb to shock once they're out outside.

I don't own a cold frame but was thinking of making a small one using an old wine crate and a propagating lid over the top. Either that or a glass panel from a photo frame. Would this work? I would prefer the propogating lid as it is higher giving more growth space,


finally with me sowing too early and not being able to plant them out till probably early may ( I live in the north east - on the north yorkshire / durham border.) when would it be best to start this process of hardening off? And if my coldframe idea would work would I be able to leave them out at night?


thank you, your advice would be greatly appreciated,






  • Hi Jack.

    I'm new to the forum too, I'm sure you'll get some good advice on here.

    I made a cold frame last year out of an old pallet-it had sides as it held roof tiles for our extension, so I pinned clear plastic sheeting all the way round and draped some over the top (after sloping up the rear side) for a removable roof. I've kept my cuttings in there all winter, they get surprisingly warm in a sheltered sunny spot so go ahead and use your scraps to make one, the taller the better.

    Your sweet peas will have a bit of a shock going out into one from the house though. It's cold at night. The trick with sweet peas is to get them bushy so you could keep them inside for 2 weeks more perhaps but move into slightly bigger pots and pinch out the tips now (leave a couple of sets of leaves below) to make them bush out rather than growing up and thin/straggly. Plenty of time to grow up later outside. You could put them into your new propogator in April. 

    Hardening off should really be 2 weeks before planting out if you can. If you use your home made cold frame it easy as you just lift up the lid in the day and put it back at night.

    If you get it a bit wrong they'll prob. still flower but be less healthy/vigorous-growth slows for a while and if you see pale brown/beige bits on the leaves they've got too cold and you'll know to do differently next year! 

    Most of us gardeners learn by trial and error. Good luck. J

  • Jack33Jack33 Posts: 9

    Thanks very much for your reply. I'll try your method in a couple of weeks then - I've already started pinching out, growth is incredibly fast which is a bit worrying ( was thinking maybe a bit of tomato feed might slow the top growth and help the roots develop more - had some shoots with tendrills appearing which I assume shouldn't happen, I pinched out. Should I keep pinching out or leave them now. I've attached a photo if that's useful. Two weeks ago we had quite a sunny day but it was windy. I decided to them outside. Within ten minutes one of them has withered ( the leftovers are on the far top right of this photo) which is the main reason for my concern, cheers again, much appreciated. 




  • Hi again. Yes they always grow fast and straggly, I pinch out more than once. 

    Sweet peas have quite long roots so if you can move them into taller pots than those before doing anything else I think they'd like it. I grow them first in old toilet roll tubes and then put them into a larger pot with a little bit of support (small bamboo or wooden kitchen skewers!).

    I think they're too young to tomato feed myself, that serves to promote flowering/fruiting, but perhaps another forum member can advise? Some new compost in a new larger pot in my view may help as the next stage as its definitely too cold to put them out.


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  • Jack33Jack33 Posts: 9
    Ah thank you, got mixed up with the NPK with the tomato feed, thought I'd read somewhere it was good for promoting root growth. I'll try find some longer pots asap. I'll begin the hardening off in my diy coldframe april.

    Thank you, you've been very helpful.

  • Jack33Jack33 Posts: 9
    Thank's for your response Holliehock. Will definitley do it gradually.

    Very helpful, cheers again.

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