I grew onions for over 20years in Cheshire on loam in 2 locations. Sunny position, pH about 6,moderate amount of manure, about 1oz/square yard of growmore.
I had good crops and enough onions from 150 sets to last a family of 6 through to April/May from August.
I am trying to grow onions in Devon on a clay patch surrounded by trees. I apply horse manure, pH is about 6-I dressed the vegetable plot with lime last winter, I use growmore at the same level as that in Cheshire.
A lot of the sets hardly grow at all and the largest onion is about 4 ounces. Some go to seed early, but much of the plot becomes shaded by trees after the end of July.
The local weeds-red campion especially are very active and I have to work to keep them down. In spite of this the crop is very poor and only lasts my wife and I through to mid November.
Any helpful thoughts please.
Regards
David T.