Cold frame question

[bario1]

Hi, i'm in the process of building a cold frame on my allotment, and i was wondering - what would be better to put on the floor inside - gravel or woodchip? I can probably get hold of woodchip for free at some point...

Cheers.

[Two_Sheds]

woodchip will rot over time, and grow fungi, and may harbour slugs.

[rustylady]

Why do you need a floor? What's wrong with just standing it on the soil?

[Aberdeenplotter]

^^^^^^^^^^^wot she said.

[bario1]

Its going to be a permanent structure, and i'm putting it on an area that has been concreted over, but the concrete isn't level... i've leveled it off with breezeblocks and subsoil from a drainage trench i dug elsewhere on the plot, but i thought it would be easier to keep tidy if i put a layer of gravel/woodchip on top of that. Also i could bury the bottom of the frame for insulation without it rotting too quickly?

[Aberdeenplotter]

okies, I understand that. To be honest, I would just level the frame to the ground and forget the gravel/woodchips. If you bury the base it will rot. Exposed it gets the chance to dry out

[ugley_matt]

Should the inside of the cold frame be painted white? I've got an old mirror looking for a new use and wondered about fixing that inside to maximise the light.

[KittyColdNose]

If you use the mirror itself there is the risk of the sun being magnified and "poooof" there it goes up in flames. Or do you mean use just the wooden frame?

[Aberdeenplotter]

A mirror shouldn't magnify unless there is some distortion in the glass and so the principles of refraction would apply i.e. light hitting the reflective surface would leave it at the same angle in the opposite direction or something like that. So light covering the veg on the way in and again on the way out.

Crikey, over 40 years since we covered refraction in a physics class in school and that's the first time I've mentioned the subject since. I actually think we used the concept of a periscope to demonstrate how it works.

[bario1]

I'm going to paint the inside white to reflect light and the outside dark green to soak up heat - if it ever gets any sun... also i thought black gravel in the bottom might warm up over the course of the day and then buffer the rapid cool down once the temperature outside drops after sundown? Who knows?

[Two_Sheds]

i thought black gravel in the bottom might warm up over the course of the day

The area covered isn't big enough, and your sun not strong enough, to make any difference, tbh

[ugley_matt]

So i plan to convert a baby changing table intoa cold frame and use polycarbonate sheeting for the walls and roof. I'll keep the roof bit clear but would i be better painting/covering the inside of the walls or leave them clear? I am guessing clear as light is everything.

[bario1]

Hi Matt, i'd definitely leave them clear, i can't see any point in painting them... mine is made of solid wood panels as the windows i got from Gumtree for the top are quite heavy.

[Linzy]

If it was mine i would line with weed membrane and coer with gravel. Should help deter the weeds and the slugs. im not sure, but i reakon wood chips could be a nice home for the slugs

[bario1]

Cheers Linzy, its actually built mostly on concrete so weeds shouldn't be a problem... i've ruled out woodchip now thanks to all the advice in this thread!