In article , Paul
writes
. Last year, being new to gardening and allotments, we planted directly
into the soil in the greenhouse but have since learned this is *not a
good idea* in the long term. Last years crop was good, but the
greenhouse had remained unused for a couple of years so the soil had
rested and was disease-free. We are planning to grow tomatoes in pots
in the greenhouse this year. Hence the question about pots. I guess
about 30cm across by 30cm deep should do. Too big, too small? OK? .
TIA for any feedback.

I use a combination of two things for toms in the greenhouse. A growbag
with a large inverted plastic plant pot on top (with its bottom cut out)
- and the sides pushed a little way into the growbag medium. This
allows you to use a bit more soil than just the growbag, getting roots
to grow a bit further up the tom stem. It also allows you to water
quickly (although from the top).

The other toms I just buy the cheap (but strong) black builder's buckets
from DIY sheds - and drill a few holes in the bottom.

--
regards andyw