Onions by Region
short day onions
Short Day Onions start the bulbing process when daylength reaches 10-12 hours.
They mature in 110 days when planted in the south during winter or early spring.
Short Day Onions mature in 75 days when planted in northern states in late spring but will not get very large; they will not reach their full size potential.
The earlier you plant short day onions, the larger they get.
Short Day Onions are best suited for latitudes of 25-35.
intermediate day onions
Intermediate Day or Day Neutral Onions start the bulbing process when day length reaches 12-14 hours.
Will produce nice-sized bulbs unless you live in far south Florida or south Texas.
Intermediate Day Onions mature in 110 days when planted at the proper time.
These are exceptionally sweet.
Intermediate Day Onions are best suited for latitudes of 32-42.
long day onions
Long Day Onions start the bulbing process when daylength reaches 14-16 hours.
These do extremely well in northern states.
Sweet, storage, and specialty Long Day varieties available.
Long Day Onions have excellent storage.
Long Day Onions are best suited for latitudes of 37-47.