Planting Bulb Onions

Bulb onions are divided into groups depending on how they response to day length. There are short-day, medium-day and long-day types.  Long-day varieties do not do well in Hawai`i.  It is best to plant only short and medium-day varieties. The time of planting is also very important.  Short-day varieties should be seeded from September to March; medium-day from March to May.  Summertime planting is not a good idea.  The short-day, mild-flavored varieties include Yellow Granex, Tropic Ace, Early Texas Grano 502, Excel and Yellow Bermuda.  The pungent varieties are Awahia and Red Creole.  Medium-day varieties include Early Harvest, Amber Express, Pronto-S and San Joaquin. Onions are shallow rooted and require consistent moisture. Under watering is more harmful than over watering.  However, excess moisture can cause a soft rot to the bulb, irrigating should stop when the bulbs are large enough to pick and the top growth begins to fall over.  Outside of Hawaii, check with your local University Extension Services to find the best time to plant bulb onions in your area.