by Birgitt Evans, Master Gardener and ABG Board Member
Last year I took a class from Master Gardener Guy Duran and finally perfected my onion growing technique. This year I grew big, fat onions, some weighing in at 15 ounces!
Onions are biennial, producing bulbs in their first year to store energy for flowering the following year. The plants are photo-periodic and are stimulated to produce bulbs by the amount of daylight around the summer solstice: long day onions produce bulbs at 14 – 16 hours of daylight, intermediate day onions at 12 – 14 hours and short day onions at 10 – 12 hours of daylight.
In our region you want to plant intermediate day onions. Check the seed packet and, if it doesn’t specify, check online for the day length for that variety. The following are intermediate day varieties available from Johnny’s Selected Seeds or Territorial Seeds: Calibra, Candy, Sierra Blanca, Cabernet, Monastrell, Expression, Scout, Red Spring & Zoey.
(Do not use sets; those are baby onions (usually long day) in their second year primed to bloom when you plant them. Onions that make flower stalks are not good for eating or storing.)
Plant your onion seeds in a seedling mix in early fall (before mid-October) and set out in a sunny place where you will remember to keep them moist. Add a dilute fish or seedling fertilizer every 2 – 3 weeks after the plants emerge. Transplant your seedlings in December or January when they are still smaller in diameter than a pencil. If they are larger than that, they will bolt and make flower stalks. (See above!)
Onions are heavy feeders so add compost and fertilizer at planting and supplement with a liquid fish fertilizer every few weeks until harvest. In June, the onions will begin to form bulbs. The stalks will fall over when they are ready to harvest. Cure with tops in a cool, dry place for two weeks and then remove tops and store. Most intermediate day onions will store 4 – 6 months, but check your variety.
With onions, timing is everything and now is the time!
