Onions- Gardening Tips from the Culinary View
as recommended by Michael Vidrine
We’ve always enjoyed having a garden to putter around in but it has become an extra special blessing these past few weeks while we stay home and stay safe.
Overall May is a pretty pleasant weather month with average highs in the mid 80’s. This is also our highest rainfall month averaging about 5 inches. Although Summer is still a ways off, May will often offer us a few days that “sneak preview” the really hot days to come. Warm season vegetables start to produce a lot this month as do some tree fruit and berries. Along with all the warm season bounty, we will also be harvesting one of our last crops planted in late winter – bulbing onions.
The onion, Allium cepa, is one of the most widely cultivated vegetables throughout the world with evidence of onions grown for food 7000 years ago. Besides the bulbing onion, there are numerous other Allium relatives that we use as vegetables including leeks, chives, garlic, shallots, multiplying onions and many others. Alliums are in the Lilly family and there are various cultivars of Alliums that are grown as ornamentals for their attractive flowers. Our garden bulbing onions are a biennial plant that we grow as an annual. The bulb of the onion is a very shortened stem surrounded by modified leaves that form scales and envelop the central bud. Each leaf of the onion forms one scale layer in the bulb so the more and larger the leaves the larger the bulb will be. As onions mature in the first year, the bulb enlarges and the leaf tops become dry. The enlarged onion becomes a food reserve for the plant for flowering and setting seed in the second year. Day length signals onions to begin developing bulbs and different varieties are categorized by how much day length is required to initiate bulb formation . Short day onions are best for our growing conditions with long day varieties best for more northern growing zones.
Onions can be direct seeded in the fall and thinned or transplanted later in the year. Many (like myself) find it more convenient to purchase onion transplants, called “sets”, which are widely available at the appropriate time for planting – usually in January and February. The plants are quite cold hardy and can stand temperatures well below freezing. Onions like relatively high soil fertility and need adequate phosphorus plus nitrogen to form good sized bulbs. Phosphorus is best incorporated into the soil prior to planting while supplemental nitrogen can be added pre planting or as a side dressing periodically as the onions are growing. In our garden we haven’t had many pest or disease problems with our onions. We rotate our plantings so that we don’t plant onions in the same bed more than once every three years. If we have a really wet spring, occasional fungicide application may be called for.
Onion sets are planted only about 1 inch deep and 5 to 6 inches apart in each direction. Sets often look a bit withered but will root quickly and perk right up. Onions don’t readily shade out weeds so the gardener will have to help with weed control. Immature bulbing onions can be harvested before they bulb and eaten as Spring or green onions. We prefer to keep a small plot of perennial multiplying onions that don’t form bulbs for our source of green onions. Weather fluctuations may stimulate some onions to react as if they have gone through two years of growth and begin flower formation. Some years we will have a few onions that will bolt and send up a flower stalk. These onions are OK to eat but will not keep well in storage because of the hollow flower stalk in the middle of the bulb. Plan to consume these onions first. Note that when an onion has begun to bolt, removing the flower stalk will not reverse or stop the changes to the bulb – the die is cast.
Onions are mature and ready to harvest when the leaves begin to dry and fall over. If some onions are a bit behind the rest, the tops can be pushed over to expedite maturing. If the weather is dry, pulled onions can be left in the garden to complete drying the leaves. If wet weather is expected, the harvested onions should be kept in a dry location until the green leaves completely whither. For storage, trim the onion leaves and roots and store in a cool dry location with good air flow to prevent moisture buildup. Onions can be kept in mesh bags or in a single layer on a screen. Some folks also keep onions in pantyhose – tying a knot between each onion to keep them separated then hanging the hose from a hook. In general, the more pungent onion varieties will store longer than sweeter varieties – 6 weeks for sweet onions and 6 months or more for the best storage onions. Chopped onions also freeze well for later use in cooking. Flash freeze the chopped onions in a single layer on a cookie sheet to keep the pieces separate then store in zip top bags in the freezer.
Onions come in red, yellow and white varieties each with slightly different taste and storage qualities. Varieties suggested for our area include the yellow varieties Texas Legend, 1015Y, Early Grano and Granex. White varieties include Texas Early White and Chrystal Wax. Some red varieties to try include Burgundy, Red Grano and Red Creole. Sets will be more limited in variety than if you are willing to grow from seed.
Onions are a nutrient dense food – high in vitamins, minerals, fiber and antioxidants while being low in calories. They are a good source of vitamins C , B6 and manganese plus a number of other minerals. When cut, onions release a gas that can irritate eyes and cause tearing. Cutting an onion under water suppresses this but then you have wet onions. Cooling an onion before cutting also reduces the amount of gas released. Over time, many who cut onions regularly get accustomed and tear less. Cutting with a really sharp knife also helps.
Onions are often eaten raw or slightly pickled like a condiment in salads, on sandwiches and other dishes. They are ubiquitous in savory recipes as a flavoring. Onions are essential in the Cajun “Holy Trinity” for sauces and gravies and in the similar French mirepoix. They can also star as the main ingredient – French onion soup, stuffed roasted onions, onion rings, onion tart and onion frittata are just a few possibilities.
Onions are always a part of our winter to spring vegetable garden and I think they would even look nice in the landscape to liven up a late winter flowerbed. A possible green ornamental plus a food crop – growing onions is certainly worth the effort.
Brazos Valley Gardener, Orchardist, Apiarist and Instructor