"H Ryder" wrote
I had the same problem, also on heavy clay. I put it down to vine weevil
despite not being able to see any. I figured that maybe in open ground
they
could move around so were less visible. Woudl be interested in knowing how
much of a problem it is likely to be though. I thought that garden plants
were supposed to be able to withstand them.

I wouldn't have thought they would be a problem in heavy clay, in my garden
they much prefer the nice soft multipurpose filled pots.
Could it be the constant wet making the roots rot? Does the plant look
healthy otherwise?
Do you get huge earthquake type cracks in the summer when it dries out,
always happened along a line of peas on our old allotment :-(

--
Regards
Bob Hobden
17mls W. of London.UK