Growing Onion Plants in a Vegetable Garden, How to Grow Onions

Easy tips for growing onion plants in your vegetable garden. Learn step-by-step how to plant and care for home grown onions. Learn common onion pests and diseases to watch for.

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For planting onions in sets, begin anywhere from three weeks before, to two weeks after, the date of the last expected frost in your area. If growing from seed, plant onion seeds after last frost. Plant a second crop eight weeks after the spring planting for raising fall scallions.

How to Grow Onions

The planting depth for onion sets is about one inch; sow seeds at ½ inch.

Any variety can be grown in containers sized 10 to 12 inches deep. Bunching onions are the most productive in small spaces. Try varieties as Beltsville Bunching, White Pearl, and Japanese Bunching.

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Caring for Onion Plants

Ensure onions receive one inch of water each weeks either by watering or from rain. It is especially important when bulbs enlarge. Stop watering when tops fall or ripening may be delayed.

Apply slow-released fertilizer or compost in the springtime. Supply onions light supplemental feedings each month through the growing season of leaf sprays or side dressings.

Three of the most important times for side dressing to be applied are: three weeks after setting out, when tops grow 6- 8 inches tall, and as bulbs start to swell.

Spray plants with liquid seaweed extract several different times during the growing season.

Pests in the Onion Patch

Onion maggots burrow into and destroy the lower part of the onion stem near the bulb. These white maggots are legless and about 1/3 inch long. To prevent the pests from becoming a serious threat, do not plant onions close together or in rows, which allows the insects to move easily from one plant to another.

Large raged holes left in the onion leaves are usually a sign of slugs. Look for slimy trails as further evidence of their presence. You can control the pests by handpicking if caught early in the season. The best pest controls against slugs are barriers set up to deny access to the garden.

Onion Plant Diseases

After planting onions, if neck tissue on the bulb becomes brownish, soft, and at times shriveled, these are symptoms of rot. Frequently a gray to brown mold develops on the surface of the bulbs. Leaves may appear water-soaked. Remove any infected plants from the garden to control the spread of the plant disease. When storing onions, make certain the necks are completely dry.

Seedlings that have the fungal disease called damping off simply topple over. You will see a watery soft rot on the stem at the soil line. Remove and destroy infected plants. When starting seeds indoors, use commercial potting soil. Disinfect tools in a bleach solution of one part bleach to four parts water.

For prevention of damping off disease on onion plants, provide soil with adequate drainage. For direct seeding, make sure soil is well-drained and warm. Stop watering for a time if you notice signs of the disease. The remaining plants may be saved if they receive plenty of sunlight, drier soil conditions, and better air circulation. There is no cure for the effected plants.

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Growing Onion Plants to Vegetable Gardening

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