Safe Sealant - What's Best To Waterproof Containers

[GregP]

Hi

In some cases I'm going to use terracotta pots for indoor plants, but also I'm going to use containers I've built myself -- small boxes with drainage, in which I'll have added a few worms.

Question: What is safe to use as a liner and sealant to waterproof those boxes.

I'd like to avoid plastic because it leaches. I don't trust glues generally, and I'm not sure about silicon either. Short of cooking up a big bowl of pine pitch in the back yard, for filling cracks and offering some protection for the wood, I'm stumped.

Thanks in advance for any opinions or advice.

[The Helpful Gardener]

Wax is an old school sealant; worried about chemicals then use beeswax (kind of expensive...)

I use soil bags to line my coco fiber windowboxes, then cut them to where they don't show; works great...

Scott