|Many of my onion sets produced double onions. What is the cause and how can it be prevented?|
|Onion sets should be 1/2" to 3/4" when planted. Large sets (3/4" and larger) tend to send up seed stalks, which halts formation of the onion and directs the plants energy into producing seed. If seed stalks are not pinched back as soon as they appear, onions can become double - or thick-necked.
These onions lose flavor in storage and are more susceptible to disease development in storage. When purchasing onion sets, try to find the small to medium sized onions. Better luck next year!