Onions

Since the YouTube posting by Barbara Lee regarding her immense onions, 4 lbs. 12 oz. was the largest; I’ve had lots of questions about onions. (To see the video, go to “Recommended Sites” on www.organichomegardener.com, click on “My Blogs,” scroll down to “My Blog Site,” scroll down to “Testimonial to Organic Gardening DVD,” and simply click on the Play button.)

The Egyptians of 4-5,000 years ago were the first known cultivators of onions. There are any number of types and varieties of onions, and generally they are of either the “Long Day” variety, or the “Short Day” variety.

Those of us in the lower latitudes, as in southern California, have relatively short summer days compared to the more northerly latitudes, as in Washington or Connecticut. While the Long Day varieties are generally successful here, we excel in the Short Day varieties.

Maui onions, Texas 509 and Walla Walla are examples of Short Day onions. The Short Day varieties are generally far milder than Long Day. The reason for that is simply that the Short Day varieties don’t absorb much sulfur from the soil. It’s the sulfur absorption that makes onions “hot,” and some varieties absorb more sulfur than others.

Onions are essentially bi-annuals. That means they are generally planted in one year and harvested the next. If you plant onion sets in the spring, they should be fully matured in about 100 days. There are varieties of onions that grow from seed to maturity in one season, but most are Long Day varieties that require 13-14 hours of sunlight per day. The amount of sunlight per day is crucial to the development of the bulb. If your onions don’t develop bulbs, the most probable reason is that they simply aren’t getting enough sunlight. The more sunlight they get each day, the bigger the onion bulbs will be.

While I’ve grown many varieties of onions over the years, both Long and Short Day, all very successfully, our favorite is the Walla Walla. I’ve grown them in the same 2 beds year after year, for more years than I can remember. In late spring, as the onions are maturing, I plant winter squash seeds or seedlings between them. As the squash plants need more and more space, I harvest the onions as the growing squash require more room. After the crop of winter squash is harvested, I plant a crop of legumes, which I chop and dig into the soil around mid-November. I let 3 or 4 of the largest and best onions go to seed, dry them in the sun and then put them in the refrigerator. (All seeds should be refrigerated until you’re ready to plant them.) Around the first of November, I start my onion seeds, 20-40 to a pot, in 1-gallon plastic pots. Between mid-December and Christmas, I transplant the seedlings into the beds, allowing about 1 square foot per seedling.

The green tops of the onions grow through our mild winters, but the bulbs don’t even start to grow until the weather warms and the days get longer. Then it seems that around the first of June the bulbs almost suddenly start to explode into huge onions. One bed gets up to an hour more of sunlight every day than the other bed. There is always a noticeable difference in the size of the onions from one bed to the next. That hour difference makes an average ½ lb. per onion in size difference between the two beds.

The soil in both beds is exactly the same, and both have always had exactly the same cultivation. The amount of sunlight is just that critical to the size of your onions.

Onions prefer a pH of 6 to 7, as do most vegetables. If you use plenty of composted organic matter, you probably already have just that pH. To onions, probably the more critical factor than having the right pH is simply having enough sunlight--the more sunlight, the bigger the onion.