[Hesse2509]

I acquired about eight 6' by 2 1/2' pieces of 10mm Polycarb twinwall back before Christmas which were once from a conservatory roof, that I had been planning to make into coldframes.

Looking at the crops that I am hoping to grow this year I realise that coldframes are not actually necessary, so I was considering what other uses I could put the polycarb to, other than stashing it for another year.

One thing my equally amateur partner in crime down at the plot suggested would be that we could use them to 'warm up' some of our seed beds, by laying them down flat on the surface, and then weighing them down with bricks.

Would this be a good idea? The only thing I would be concerned about personally would be the inability of moisture to get through to the soil, but then I suppose the same thing can be said for damp-proof membrane.

[Trillium]

It would certainly heat up soil and kill off some weeds, but as you say, it would really sweat the soil and also kill off beneficial worms. True, it will also kill wireworms and other pests, but the good will die as well. I had a small sheet of this stuff that sat on the ground for a while, and the grime and slime that quickly accumulated was a beast to remove when I needed the piece for a project.

Normally cold frames are used to harden off plants from house/greenhouse to outside. more to adjust them to the cooler outside temps and protect them from surprise frosts until it's planting time. Your area might benefit growing cukes/melons in cold frames which would contain the heat these plants need more than others.

[mumofstig]

You certainly could use them to warm the soil, I'll soon be putting some polysheeting down for a few weeks, as usual, so I can sow some early peas. The soil needs to keep all the moisture it can as we are sposed to be getting another dry spring.

I don't think they're in place long enough to do any damage tbh

[bigben]

If you put it down with something to keep it an inch or so off the ground then you will get the heating effect but air can still get in. Put down a few bits of wood or even lay a hose back and forth then lay the plastic on top with something to stop it blowing away. A few weeks to help warm the soil should not do any harm.

[solway cropper]

I got hold of some similar material and made long cloches out of it by hinging two sheets with wire twists pushed through holes I drilled. You can open them out to make a 'tent' but they fold flat for easy storage.