Onions (Allium cepa)

by Robert H. and Hoberly Schuler

With so many varieties of onions to choose from, it is important to know their growing conditions. Common environmental conditions affecting plant growth are temperature, nutrients, water, sunlight, pests and air quality. The proper development of onions in the fall requires seeds or plants of a “short day” lengths variety such as Grano, Granex , California Early Red or Crystal White Wax (white Bermuda). Yellow or white Spanish and Globe are “long day” varieties for “spring” planting.

Boiling and pickling onions can also be planted now but it is best to plant them three or four months before you want them for pickling. Green bunching onions that do well in our area include Evergreen White, Southport White, White Lisbon and Tokyo Long White. These onions can be planted every three weeks from September through March and are ready for harvest when they are ¼ to ½ inch in diameter.

Onions sets are a good method for producing a quick crop of green onions. The disadvantage of “onion sets” from our retail nurseries is that they are may not be adapted to your area and tend to fail to mature as most are “long day” varieties.

The time to plant onion seeds for “short day” variety is November through March, (the inland valleys Oct. & Nov.)

We are fortunate to have onion sets available in pony packs at most nurseries. Transplanting into the ground three inches apart is easier than spacing seeds. To be certain that you have seeds of “short day” or “day/neutral” varieties you must order from the seed catalogs early in time for planting.

Seeds and transplants planted now will yield a crop by next spring.

“Long day” onion seeds started in Jan. or Feb. will initiate a bulb by June for a July-August harvest.

Prepare a row of loose, well drained soil with plenty of mulch (use your compost mixture) in full sun. Place a soaker hose down the center of the row for watering, to keep the onions slightly moist. Place the seeds 3” apart on each side of the hose, and cover with a light soil ¼” deep. If you sow the seeds more heavily, use the young plants as scallions or replant in another row (final spacing should be 4-5inches apart).

Onions like a light feeding of a balanced fertilizer every three weeks or use a liquid fertilizer until the bulb starts to form (feeding nitrogen after this period could make the bulbs split). Keep the weeds pulled so as not to compete with the shallow roots of the onion.

Onions are grouped according to strong flavored “American” and mild or sweet sometimes called “European”. The American onion produces bulbs of smaller size, denser texture, stronger flavor, and better keeping quality.

In general, the softer varieties such as Grano and Sweet Spanish are milder than the harder varieties such as Southport White Globe. The mild onions are preferred for fresh consumption, but the stronger flavored ones are better for cooking.

The onions are ready for harvest when the tops fall over (approximately six months after planting). Pull onions and let them dry for a few days on top of the ground. Cover the bulbs with the tops so they will not sunburn. When the tops and “necks” are dry, remove the tops and store the bulb in a cool dry place. If the onions are allowed to form seed stalks, the center of the bulb becomes woody, undesirable to eat and unsuitable for drying.

Shallots can be a continuous crop source in your garden. Use the tops as you would green onions. They will form many bulblets for future planting when the tops are dry.

Question: Is it feasible to make a soil probe for checking how deep the soil in my lawn is being irrigated?
Charles, Laguna Beach

Answer: Yes, making a probe is a great way to water correctly and save money.
Soil probes can be made from a 3/8” blunt-pointed steel rod about three feet long with
a one-half inch diameter handle welded to the top (a 2” piece of hardwood with a 3/8” hole-1” deep for the rod can be substituted for a handle). When you push the probe into the soil, the probe will resist further pressure when it strikes dry soil. A very large screwdriver can be used as well.

Question: Should my cymbidiums be fertilized this month (October)?
Mary, Santa Barbara

Answer: Cymbidiums should have a bloom-promoting fertilizer, such as a 15-30-15 water-soluble formula applied every month until buds start to form. If the leaves are dark green, try to place the plant where it will get more sun in the winter which will make the leaves yellow-green.

Do you have a garden question? Contact Master Gardeners Robert & Hoberley Schuler at rhschuler@verizon.net
rhschuler@verizon.net
To view previous articles visit www.californiagardenclubs.org/Features/garden_pointers

GPP# 007 for 10.25.08 – Onions, Garden probe, Cymbidiums

Copyright 1998-2008 California Garden Clubs, Inc.
... the non-profit federation of garden clubs in California representing more than 22,000 California gardeners.
For problems with this website, please contact webmaster@cagardenclubs.org