Yellow Onion –
The onion is a perennial that’s grown as an annual root vegetable. Unknown in the wild, Allium cepa may descend from several species found across Central Asian to include Allium oschaninii, Allium praemixtum, Allium vavilovii, Allium pskemense, and Allium galanthum. It has a long cultivation history and is intrinsic to many culinary cultures.
The onion plant produces a dense upright cluster of hollow pale green leaves that rise from a bulb that grows larger and more bulbous as the season progresses. White or lavender-pink balls of star-like flowers emerge from plants in the spring of the second year, though these are rarely seen because plants are generally harvested after the first year. Some varieties also produce stems topped with clusters of small bulblets (bulbils) at their tops.
Onions may be round, flattened or torpedo-shaped and red, yellow, or white. They are true bulbs with distinctive rings and are surrounded by a papery outer covering. Some onions are pungent while others like ‘Walla Walla’ are known for their impressive sweetness. Those with a higher sugar content don’t store well whereas more pungent varieties keep better.
Garden onions are categorized by the day length needed for them to form large bulbs. Short-day varieties, which require 10 to 12 hours of daylight, are typically planted in fall to early winter, and produce bulbs in the spring. Short-day onions are usually sweet, but do not store well. They include ‘Bermuda’, ‘Grano’, and ‘Supersweet’. Intermediate-day onions such as ‘Red Torpedo’ and ‘Ringmaker’ require 12 to 14 hours of daylight, and are planted in the early spring and harvested in the fall. They store moderately well. Long-day onions need 14 to 16 hours of daylight to form bulbs and are best suited to subarctic regions. The extremely long days there result in pungent onions that store well.
It is necessary to provide these veggies with even moisture as well as full sun and rich soil. Onions can be seed grown but most are planted using sets, or small bulbs. Sets should be planted with their tops extending just above the surface of the soil. Harvest your onions when their leaves start to show decline. Good keepers should be stored in a dry, cool, well-ventilated area.
Onions are fun to plant and great for kids, Try braiding their dry tops to make an attractive hanging onion cluster for fall.
Winchester Gardens generally stocks this item.
Annual – Edible
Spring, Summer Fall
White, Green, Yellow Green, Gold, Pink, Lavender
Green, Light Green, Gray Green
Select a site with full sun and well-drained soil. Prepare the garden bed by using a garden fork or tiller to loosen the soil to a depth of 12 to 15 inches, then mix in a 2- to 4-inch layer of compost.
Choose onion sets that are 1/2 to 3/4 inch in diameter for best results. Plant your sets early in the spring — onions do best if the temperature is cool when they start to grow, and warm as they mature. There’s no need to make trenches or special holes for the sets. Just grasp them at the top (the pointed end) with the root end down and push them into well-prepared soil the full depth of the bulb. The soil should just barely cover the top of the onion sets. If you have some tiny sets, plant them at least an inch in the ground, so they get good contact with the soil. Space sets 4 to 6 inches apart. If starting from seed, sow seeds indoors 2 to 3 months before your last frost date or sow seeds directly in the ground as soon as the soil can be worked in spring. You can also buy started plants or sets for spring planting. Set transplants 4 inches apart after all danger of heavy frost is past. For mild winter areas of the South and West, grow short day varieties in fall and winter for a spring harvest.
Keep onion bed well weeded and water plants during the summer if rainfall is less than 1 inch per week. Contact your local County Extension office for controls of common onion pests such as root maggots.
Pick scallions or green onions when they are 6-8 inches tall and a bulb has begun to form. When the foliage of bulbing onions begins to die down naturally, withhold water. A week later, pull the bulbs and place them in a warm, dry location. When the skin is papery, cut off the foliage, leaving a 1-inch stub above the bulb. Store dried bulbs in a cool, dark location. Harvest shallots after side bulbs have formed and the tops have begun to dry. Separate the side bulbs, dry them, and store as you would onions.
Beet, cabbage family, carrot, chard, lettuce, pepper, strawberry, tomato. Chamomile and summer savory improve growth and flavor. Pigweed raises nutrients from subsoil and makes them available to the onions. Sow thistle improves growth and health.