"hillier" wrote
Last year my onions were a disappointment as the greenery collapsed and
lay all over the onions. What can I do to improve things this year ?
When they are coming to the end of their growing onion tops naturally fall
over and dry off but I suspect it wasn't at the end of the season you had
this happen. Was it a very bad case of rust, or powdery mildew perhaps or
even Leek Moth? Did you notice any pests/disease?
If you want big onions space them at least 9 inches apart with rows 12
inches apart. This also gives you space to hoe between them.

A rough idea of you location would help too.

--
Regards
Bob
In Runnymede, 17 miles West of London