Light conditions.
8x12 greenhouse aligned n-s with a seven foot hedge to the east, a hazel bush to the north, a four foot high perennial bed to the south end and open to the west with an apple tree some distance away to the south-west. Some pictures on my blog of it under construction.
Ground conditions.
Was my vegatable plot some years ago, then became a lawn. Turf skimmed off and then soil dug over.
Prime Suspect in my view.
Soil, as I did not dig anything into it

and it is starting to look very clayey after watering.
Life is a learning process.
The original question was because the pots and ground plants are three foot apart in the same greenhouse.
I think at the end of the year I will subtract a few barrowloads from the beds and substitute some regular horse doings in chopped cannabis.