It's been a few years, but I'm still keen to understand why porous terracotta is not permitted. If it's about moisture, this can be solved by putting a plate or dish under the pot. But it can't be about moisture, because
wood is allowed, and wood is far worse for moisture wicking in this respect.
Terracotta is much more
sustainable than glazed ceramics (which are higher temperature, higher
energy, often higher quantities of toxic gick due to heavy metals in glazes), and its exclusion is a question mark for me. It's also one of the most accessible non-plastic options and this restriction seems to have limited the uptake of
PEA's
gardening section.