Hello happy gardeners. Fall is nearly here and those of us with small gardens have most likely pulled what was left of the summer crop to make room for the fall/winter season. Those of us with larger gardens still have some straggler tomatoes or perhaps some late season squash hanging around but soon those too will end up in the compost pile. I’d like to take some time today and over the next few posts to talk about the varieties of crops that we grow in Tucson and in the low desert during the cool season. I’ll be starting with today by discussing onions, one of the most beneficial crops for the organic garden.
Growing Onions in Tucson
I can say with all honesty that the onion and it’s relative garlic are perhaps the best plant companions an organic gardener can have. The carrot family’s ability to attract beneficial insects comes close, but the crops in the carrot family just don’t have the culinary diversity that the onion family has. Onions are excellent repellers of both above ground and below ground pests and are excellent companions to most vegetable crops. For these reasons, no organic garden in Tucson should be without at least a few onions. You can interplant onions amongst all of your winter garden greens but avoid placing near peas.
Growing onions in Tucson and in the low desert can be very confusing, after all there are so many types to choose from and generic planting dates on the backs of seed packets only add to the confusion. It is my goal to take some of the mystery away so that this year will be your best year yet growing onions. All types of onions will grow during the cool season, however, depending on the type of onion, you may need to delay planting to the end of winter to achieve the desired result.
Starting in mid-late august, organic gardeners in Tucson can begin planting green bunching onions from seed. Although bunching onions are perennial,
most gardeners grow them as an annual crop and pull them in the spring. Bunching onions like scallions are grown for their green tops rather than their bulbs. Varieties such as Evergreen, and Ishikura are known to do well in our mild winter climate.
Chives, another bunching member of the onion family, can also be planted during the early fall and can be harvested much in the same way you wold harvest green onions. Leeks, which have a much longer growing season, also do well in Tucson gardens and can be planted at this time, however, they’ll require a little more space to grow to their full potential.
My favorite onion is the Tohono O’Odham multiplier onion, I’itoi. I’itoi onions were brought to our region by the spanish in the late 1600’s and were first cultivated on Boboquivari Mountain. The O’odham nation regard Boboquvari Mountain as their most sacred site and as such, the I’itoi was named after their god of creation who they believe resides in a cave at the base of the mountain.
I’itoi onions can be compared to shallots, but they produce smaller bulbs with a more peppery flavor. The green tops are an excellent replacement for scallions in any dish, but they are particularly tasty in southwest cuisine. A single bulb can clump to produce dozens more. Plant in late September through October and harvest when the tops begin to die back in late May or early June.
Bulb onions will grow throughout the cool season if planted from seed, however the bulbs will not grow large until the day light begins to lengthen in the spring. If all you are after are the greens and pest control, the this seed planting method works great. However, if you want large bulbs like the ones in the grocery store, then you’re going to have to hold off and plant onion transplants in late winter.
Bulb onion sets or transplants sold in catalogs are divided into three types, long day, short day, and intermediate day. If you want to grow large onions in Tucson, then choose short day transplants and varieties such as Red Creole, Red Torpedo, Yellow Granex, and Texas Early Grano. Onion transplants can be obtained locally at farmers markets or through seed catalogs and specialty growers starting in December or January. Many Growers also offer the option to pre-order for next year.
Caring for and Enjoying Your Onions
Growing onions in Tucson begins first with the proper growing environment. Onions, like most fruits and vegetables, prefer soil that is well draining and contains large amounts of organic matter. They prefer a moist soil but one that is not water logged. Onions also like soil free of large rocks. Amend our native soil with generous amounts of compost and worm castings. Be sure to also add soil sulfur and some bone meal or fish bone meal to give your onions an extra boost. Onions are light feeders, but a bi-monthly or monthly application of compost or worm casting tea will do your plants wonders.
If you are growing onions for their greens, then you can begin to harvest when the tops reach a height of about 6 inches. For bulb onions and I’itois, harvest the entire bulb as soon as the tops begin to die back in late spring early summer. Allow the bulbs to dry or cure completely before using in the kitchen. Store bulb onions using an old pair of panty hose. Simply add an onion, tie a knot and add another and so on.
If after reading this post onions are still puzzling you, please leave a comment on my contact page and I’ll be sure to get back to you. If you’d like to purchase onion seeds or transplants, visit your local farmers market or visit the links below for more information.