By Waterbloke
Essex,
United Kingdom 
Hi Everybody,My question is I have made some wooden planters that I will line with black membrane to stop any contamination from the wood into the compost and into the plant roots. They will have plenty of drainage, my question is would it be an idea to place some sponge like an ex memory foam in the bottom to act as a reservoir for water so the planters will not dry out so quickly especially in the full sun. The memory foam is about 2 inches thick. Is this particular foam toxic to plant roots any body done this before or any advice would be appreciated Thank you
19 Feb, 2023
Answers
and what did you find out Waterbloke? is it a good idea or not?
curious to know.
20 Feb, 2023
I tried this in a hanging basket once but in a large container
I tend to use moisture granules. These give you uniformly damp compost rather than the puddle at the bottom effect. You'll still need a drainage hole of some sort though. I wouldn't risk plastic over the whole base as you stand a good chance of the base of the container rotting under your plastic layer.
20 Feb, 2023
Thanks for that advice but I have quite a few planters that I have made and wouldn,t have enough material to line them with. I have done some research and found an answer about the use of foam so basically i have answered my own question thanks again
20 Feb, 2023