Sweeter by the dozen: Peel back some Sonoma County sweet onions for dinner

The sheds of Tierra Vegetables Farm on Airport Boulevard now hold drying bins full of “Big Red Burger” sweet red onions. Lee and Wayne James, brother and sister farmers, planted them in December, and as the days grew longer, the onions grew bigger. They'll sell out by September.

But fear not, for they planted their fall crop of “Spanish Sweet Yellow” onions in March. This storage type slowly matures over summer and will be harvested in September, just when the red sweets are gone. They store well, so they'll be sold throughout the winter months.

And so the great cycle of the seasons turns and keeps giving us onions. We need them, for as the saying goes, “Every great meal begins by chopping an onion.”

The big onions with loose, shaggy, papery skins are in the stores and farmers markets now, the first full-sized onions of the new growing season. They're sweet and juicy and perfect for omelets and salads. In a month or two, we'll find the new crop of smooth-husked, tight-necked storage onions to get us through the fall and winter. But now is the season for sweet onions.

Onions aren't usually sold by variety name, but a sign may indicate which onions are the sweet kind. If the produce manager or farmer is on his or her game, the sweet onions may be sold by variety name: “Walla Walla,” “Maui,” “Vidalia,” “Yellow Granex” and “Texas 1015Y” are among the most popular. Sweet, red onions like “Big Red Burger” are also less pungent and sweeter than storage onions.

Sweet onions are about 5 percent sugar, more than double the pungent yellow and white storage varieties, and Vidalias can be even higher in sugar than that. And that's their charm. They aren't as tear-jerking as the standard storage onions, but their sugar allows them to caramelize in the pan, turning a rich brown and concentrating their sweetness while giving it a caramel edge.

This makes them perfect for making French onion soup, for frying to top hamburgers, to add to stews and for making mirepoix and the Cajun flavor base called The Holy Trinity: onions, green bell pepper and celery.

Because they're milder, sweet onions are also perfect for serving raw in salads and salsas, so you can chop away without worrying about tearing up.

The tight-necked, locally grown storage varieties that will show up in September are the familiar onions we find in Safeway and outlets like Whole Foods and Oliver's, along with farmers markets. Once you get them home, they'll store in a basket at a cool room temperature for three weeks or more. Just make sure air can circulate around them. If they sprout or become soft, chemical changes in the onion flesh can turn their pungency into bitterness.

Most familiar kinds of storage onions are dependent on day length to know when to stop growing and get ready for those months they'll spend in storage.

The number of hours of sunlight available each day started shrinking after June 21, so in early July, local onion growers feel the necks of the onions planted around the middle of March. If they are soft and easily bendable, then the tops are pushed over. This is another signal to the onion to start the curing process. Pushing over the tops also signals the tops to dry out and turn brown. Some varieties, like “Spanish Sweet Yellow” take an extra month or so to completely mature.

Right about now, most storage onions have been pulled and are resting in the shade on trays that let air circulate around them. The outer layers of the bulbs dry out and brown into papery husks. The necks shrink, sealing off the moisture in the bulbs so they don't dry out and keeping out rots and molds.

Commercial onions that appear in stores over the winter are kept in cold or controlled atmosphere storage. Small farmers and home onion growers may not have the right conditions for cold storing, so most small growers grow both sweet and tight-necked storage varieties.

For home gardeners who want to grow their own, visit dixondalefarms.com. This Texas company's website is a trove of information about how to select the right storage onion for our intermediate day zone here in Northern California. You'll also be able to find a wide range of sweet onions in Dixondale's catalog.

Each year I devote an entire raised bed to onions, half to Texas 1015Y and half to a rotating selection of storage onions. The sweet Texas 1015Ys are named for the state where they were developed and for the ideal date for planting seed there, October 15. The Y stands for yellow. These sweet onions will last for about three months.

Onion culture is simple. Give them fertile, well-drained garden soil well mulched to keep out weeds. Onions are only persnickety if their beds are allowed to get weedy. Keep them watered during the months up to the summer solstice. Back off water after that, as you want them to dry and cure.

Nutritionally, onions have good stores of beneficial sulfur compounds, vitamins B6 and C, and antioxidant compounds like quercetin and anthocyanins. And they add their rich flavor to just about any dish.

The rooster's beak, which is the English translation of the Spanish name Pico de Gallo, should be spicy enough to make you sit up and take notice. That's the way it's served in authentic Mexican restaurants. It's a required topping for any taco. Or serve it with tortilla chips as a snack.

Pico de Gallo

Makes 4 cups

1 1/2 cups diced ripe tomatoes

1 cup chopped yellow or red onion

1 1/2 cups diced avocado

2 serrano chilies, minced

3 tablespoons fresh squeezed lime juice

1/4 cup chopped cilantro

- Salt and fresh ground black pepper to taste

Combine all ingredients in a bowl, cover and refrigerate for two hours so the flavors can marry.

Jeff Cox is a Kenwood-based writer who can be reached at jeffcox@sonic.net.