DIY heated cold frame

[StephB]

Hi all

I have a large polytunnel but i always struggle germinating early seeds this time of year and end up with windowsills covered in seed trays germinating tomatoes and chilli's which end up going all leggy if im not careful.

I have a brickbuilt shed out the back of the house which has power to it. I am wondering about trying to build a brick rectangle against the shed wall and use a sheet of clear polycarbonate over the top and buying a waterproof heat pad to sit maybe 6 seed trays on to save me having them all in the house.

Has anyone else done this? How do you all germinate you early Jan/Feb seeds?

Any tips would be appreciated.

thanks

[veggiechicken]

Hi Steph and welcome.
I would think you'll be able to germinate the seeds with base heat but I'm not sure that it will be enough heat to keep tomato & chilli seedlings growing if we have a cold spell.

Someone who knows about these things will be along soon.

[Jimny14]

Your cold frame build idea is great and I'd build it anyway just to have as a cold frame. I'm not convinced about the heat pad being enough to keep it warm enough to germinate and keep seedlings growing this time of year though I'm afraid. I think it's likely your seedlings will turn their toes up at the next cold snap I'm afraid. Now, inside the shed if it has a window is a different prospect. If you could build an insulated box (expanded polystyrene blocks are good for this) with a polycarb front on it with a heat mat inside it inside the shed (likely frost free) then you could be on to a winner.

[SarrissUK]

I haven't got a coldframe, but if something is close to the ground, the cold gets drawn in from underneath through the ground too, which makes it harder to keep warm. Its always fun to experiment though, so get it built and try it out!

[StephB]

Thanks for your replies.

I have been reading the heat mat description on Amazon and it is supposed to raise the ambient air temp 10 - 20f higher. Think you are all quite right though that during a hard cold spell it will still be too cold for Chilli's and toms.

I need a conservatory

Do you all propagate yours on your window sills?

[veggiechicken]

I propagate in a heated propagator indoors. Doesn't take much room up if you stagger your sowings.
The problems start when the seeds have germinated and you need to take the seedlings off the heat and into good light. You also can't shock them by putting them straight out into an unheated greenhouse.
Its a difficult one to get right.

[SarrissUK]

I use a pasting table that gets a huge tray on it that is placed in my large bay window in my bedroom. The dressing table gets to spend half the year in the middle of the bedroom lol

[Doncasterpaul]

Great idea. However as the other posts say the heat pad will not be strong enough to heat or make any real difference. Also as it will be constantly on. How long will the heat pad last before it breaks down etc

[Cadalot]

I set up a grow station in the brick shed on top of the freezer See Alans Allotment: More Modifications To Grow Station 2

I also set up some portable stations with LCD Panels in the office see Alans Allotment: Tomatoes in Grow Station

[goodolpete]

I’ve got a 3ft by 2ft by 6ft high greenhouse that I erect every Feb against my extension.
I do winemaking in my garage using a 2ft by 1 1/2ft plastic container filled with water and
heated with a thermostatic aquarium heater so the demijohns in the container have a
constant temperature. The thought struck me a couple of months ago that I could put the
container in the greenhouse (lined with bubble wrap) and kill 2 birds with one stone.

[4Shoes]

Do you have a easy supply for fresh muck. Build a mini polytunnel in your polytunnel.


Essentially a 1.2 sq or 1.2 x 2.4 frame between 600 and 900mm high covered in compost and a hooped pipe plastic covered frame.

see this thread for ideas on how to create hooped frame
https://www.growfruitandveg.co.uk/gr...che_98391.html

and this for ideas for cover
https://www.growfruitandveg.co.uk/gr...bed_98393.html


The old heap can be used to grow plants in over the summer before you empty and reuse following year. or just tip into your compost heap. + side no energy needed,