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The Humble Gardener

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Growing Onions in Central Illinois

While visiting some Amish friends years ago, Chip and I were invited to visit their vegetable garden. I had seen it when we parked and was eagerly anticipating the tour. Their garden was huge and flourishing. Of particular interest were the enormous onions. I noted that they were different varieties, evident by the yellow, white, and red bulbs showing through the light mulch. I asked our friend David the secret of such huge onions in early summer. He smiled and inclined his head toward the pasture where his buggy horses were peacefully munching. The drying manure pile told me all I needed to know about the ready-made, organic fertilizer that David was using on his onions.

The horse fertilizer was not David's only secret to growing successful onions. Granted, onions are pretty easy to grow. They are usually the first crop that we plant each spring. But whereas Chip and I always planted sets (little brownish bulbs sold in nurseries and big box stores' garden centers), David used transplants. These literally are little onions with a green top. Using these jump starts the growing season vs planting onion seeds or sets.

I couldn't replicate David's source of fertilizer-I was pretty sure the city fathers of Galesburg would not allow horses within city limits-but I could plant transplants. I found some locally but made a major error.

I thought the local stores sold transplants that would grow in this zone. I duly purchased the plants, went home, worked the garden soil, adding peat moss and compost, and planted the transplants. I figured I could plant them fairly close together and harvest scallions (green onions) for cooking, leaving space for the remaining onions to form bulbs. The theory was spot on, but unfortunately, the onions I bought were a mix of short day and long day onions. Who knew? I thought onions were onions.

Long day onions need 14 to 15 hours of sunlight to form bulbs. Short day onions need 10 hours. Long day varieties are for northern growing areas (above the 35th latitude); short-day varieties are for southern. If short-day varieties are grown in our zone, they won't do well. They will not form bulbs of any decent size. And since the long day onions need more daylight, they will not do well in southern climates. (Intermediate day/day neutral day onions have been introduced but I have no experience with them. They require 12-14 hour days to bulb. These can be grown in our zone.)

So lesson learned. The next year, we ordered onions from and judiciously checked the onion transplants in local stores for Walla Walla, Copra, Yellow Spanish, and White Spanish onions, long day varieties. Dixondale sells long day samplers so we ordered these as well. It helped to have a variety to see which would grow well and which would store well.

Having resolved what to plant, we turned our attention to how to plant. Onions can be planted in late March and early April. They are easy to grow but they do need some special treatment from the beginning. The soil has to be loose enough to allow the onion to form a bulb. Obviously, the harder the soil, the smaller the bulb. Adding compost and peat moss to the garden rows provide a perfect environment for the transplants. The bottom of the plants should be covered but not too deeply. You don't want water sitting on the green part of the onion so planting the bulb about halfway should keep the plant from getting waterlogged. As the bulbs form, they will come up out of the soil. Let them.

We plant all the same variety together in rows that are closer than most people plant their onions. Usually gardeners leave 4 to 5 inches between each plant, but we like to pick some onions when they are green/scallions so we plant them closer and thin (pick) onions before they form bulbs. The vacant space then allows the remaining onions to have enough room to bulb.

Onions need at least 1" of water per week (rainwater counts), and they need fertilizer every 2-3 weeks. Barring a charity-minded horse at your beck and call, you can use a fertilizer such as Miracle Grow or other commercial fertilizers. Side dress the plants by applying the recommended amount of fertilizer next to the plant and incorporating it into the soil. Light mulching will help retain moisture and keep weeds down.

Within weeks of planting, you can enjoy scallions in stir-fries and salads. Large slices on hamburgers or grilled Portabella "burgers" are crisply delicious. Homemade onion rings are indescribable when made from homegrown onions. And the onions that you store and use all winter will remind you to plant this versatile crop come spring.

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