Growing Onions

Onions are a good addition to most gardens, with varieties to suit most every climate. Most onions are sensitive to the length of the day. Bulb-type varieties are classified as either long-day or short-day onions. Long-day onions will produce bulbs when grown in the summer months in the North. Short-day onions produce bulbs in the mild winter climate of the South. American onions and Spanish onions need long days to produce their bulbs; Bermuda onions prefer short days.

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Long-day bulb onions need long
summer days to produce their

Onions are also sensitive to temperature. Generally, they require cool weather to produce their tops and warm weather to produce their bulbs. They're frost-hardy, and you can plant four weeks before the average date of last frost. In the South, onions can be planted in the fall or winter, depending on the variety.

Onions are available in three forms: sets, transplants, and seeds. Sets are small bulbs that are dormant. The smaller the sets are, the better. Sets are easiest to plant, but they come in the smallest number of varieties. Transplants are usually more reliable about producing bulbs and are available in more varieties than sets. Seeds are the least expensive and offer the greatest number of varieties, but they take the longest to develop and are most prone to disease and environmental problems.

Onions need a well-prepared bed with all the lumps removed to a depth of at least 6 inches. The soil should be fertile and rich in organic matter. Bulbing onions need full sun, but green onions can be grown in partial shade. Plant transplants or sets 1 or 2 inches deep and 2 to 3 inches apart. If you're planting onions from seed, plant the seeds 1/4 inch deep and thin to 1 to 2 inches apart. If you have limited space, you can grow onions between other vegetables, such as cabbages or tomatoes.

The soil should not be allowed to dry out until the plants have started to mature, which is marked by the leaves starting to turn yellow and brown and droop over. At this point, let the soil get as dry as possible.

Harvesting Onions

All varieties can be eaten as green onions, though some varieties are grown especially for their bulbs. Harvest leaves whenever you need. Harvest green onions when the bulb is not much larger than the leaves. Harvest dry onion bulbs after the leaves have dried. Lift the bulbs completely out of the soil. Dry the bulbs thoroughly before storing.

There are more kinds of onions than you can shake a stick at. If you're confused, keep reading -- in the next section, we'll talk about the different onion types.

Want even more information about onions? Try these links:
  • Why do onions make you cry? Grab a tissue and find out just what it is about onions that brings on the waterworks.
  • Vegetable Gardens: Grow a full harvest of great vegetables this year.
  • Gardening: We answer your questions about all things that come from the garden.