Best wood treatment for raised veg. boxes
Hi all, I'm just about to embark on building vegetable boxes. The wood has already been bought - its just pine wood that is untreated which was all we could realistically afford.
So I want to treat the wood to help it last as long as possible, and I've spent hours and hours searching the web for what is best and safest to treat the wood with. I just don't want anything that is harmful to the plants or humans.
After getting nowhere, I don't know whether to now just use any wood treatment regardless of if it is natural or organic and just line the inside of the vegetable box with a plastic sheet to stop any chemicals leaching into the soil, or if there are any treatment products that are safe to use, are available in the UK and don't drastically alter the colour of the wood (i.e go from a light pine colour to almost black for example).
Any input would be extremely appreciated, thanks.