Sorry for the late reply, but I think that the issue is t hat the pots get too hot.
They get enough water and the drainage is good. I just think that the pots (kind of) cook the plants.
The soil was arable and loose when starting, but within a short period it had baked into a hard rock.
That...
I spoke with their support folks about a problem i was having and they sent me three more gaskets and suggested doubling up on the gaskets in the lid.
Not to hijack this, but have you thought of a way to use a temp probe with this?