I lined my raised veg bed with old compost bags, and a home-made wooden planter with a tarpaulin. Both held in place using a staple gun. Plastic I think is better than cardboard as it helps retain the moisture in the soil, which will dry out faster than the ground. Weed membrane is porous so won't do this as well but others who have tried it will know more!
"If you have a garden and a library, you have everything you need"
Posts