Greenhouse floor/base advice please

[Buildinganark]

Hello! I've inherited a greenhouse that has a layer of slate chips as the floor. As far as I can see there's membrane then ground underneath. I love my greenhouse - but think the spilt compost/soil etc will just be a breeding ground for weeds and bugs. I can't afford to have it replaced. Can anyone recommend a matting material I could lay over the slate - that would let water through but not soil etc?? It needs to be cheap!
Thanks.

Anything that let's water through will let weeds through too. Do you want to grow things in soil beds either side of a central path (that's what I do)? If so, you could scrape the slate into the middle to be the path, lift the membrane,down the sides, and cultivate the soil. If you put some timber along the edge of the slate to hold it in, this should solve your problem and won't cost very much at all.
think of all the lovely tomatoes and salads!

Thank you @FizzingAda that's a really good idea. (I'm now to all this!).