How to Grow Onions

Elizabethan herbalists used onions to treat maladies ranging from head colds to baldness. Today, most people simply eat them, raw or cooked, in about a thousand different ways. Onions are warm-season veggies and, however you plan to use them, you can grow them anywhere.

Difficulty:

Moderately Easy

Instructions

Things You'll Need

• Compost Makers
• Fertilizers
• Floating Row Covers
• Garden Spades
• Garden Trowels
• Mulch
• Plants
• Seeds
• Shovels

1. Buy started plants at the nursery. Otherwise, start seeds indoors 8 to 10 weeks before the last expected frost (see "How to Start Vegetable Seeds Indoors").

2. Choose a site that gets at least 6 hours of sun a day and has soil with a pH of 6.0 to 7.5. Onions need moderately fertile soil that is well-drained but retains moisture. Digging in plenty of compost before you plant will ensure the right combination.

3. Till the soil to a depth of at least 8 inches to allow good bulb development, and remove all traces of weeds - they can easily overtake young onion plants.

4. Deter cutworms and maggots - the onion's archenemies - by adding parasitic nematodes to the planting area. You can buy them through mail-order catalogs and at many nurseries.

5. Harden off transplants, whether store-bought or homegrown, and move them to the garden two to three weeks before the last expected frost.

6. Set plants into the ground slightly deeper than they were growing in their pots, spacing them 2 to 6 inches apart, depending on how big the mature bulbs will be. (Check the seed packet or a comprehensive gardening book for details.)

7. Cover the seedlings with floating row covers to keep maggot flies from laying eggs. Weed frequently, taking care not to disturb fragile onion roots.

8. Feed plants with compost tea (see "How to Make Compost Tea") three times: three weeks after planting, again when the tops are 6 inches tall, and finally when the bulbs begin to swell. Avoid fertilizers high in nitrogen; they encourage lush tops and tiny bulbs.

9. Cover bulbs lightly with compost or other organic mulch if they start pushing out of the ground. The exposed surfaces are prone to sunscald.

10. Provide about an inch of water a week until the tops begin to fall over or turn yellow - signs that the bulbs are reaching maturity - then stop watering.

11. Start harvesting scallions, or green onions, when the tops are about 6 inches tall; the larger the plants grow, the stronger their flavor becomes. Begin pulling onion bulbs as soon as they're large enough to use.

Tips & Warnings

• To mature properly, different onions need different amounts of light and darkness. Varieties are grouped by day length: short, long and intermediate. Seeds are marked accordingly in catalogs, and your local nursery will have plants that are bred to thrive in your area.

• All members of the onion family can fall victim to pink root, a disease that stunts roots and turns them pink or red. The problem befalls commercial growers more often than home gardeners, but to be on the safe side, buy disease-resistant varieties and rotate crops each year.

• Onions thrive in containers. Choose a pot at least 12 inches deep and 8 inches wide with good drainage. Fill it with compost-enriched potting soil; water frequently and apply compost tea every three weeks.

• For best results, avoid starting onions from sets, which are dormant bulbs of dime to quarter size. They tend to yield seed stalks rather than bulbs, and what bulbs they do produce rarely store as well as those grown from seed.

• Onions like cool weather but not prolonged cold, so don't rush to get them into the ground; extended temperatures in the 30s and 40s F will slow development.