onions

Growing onions is relatively easy. Harvest early for green onions, or later for larger bulbs.

Onions are a cold-season crop, easy to grow because of their hardiness. Onions can be planted in either the spring or fall. Onion plants grow well in raised beds or raised rows at least 4 inches high.

VARIETIES: Onions are sensitive to day-length, so varieties are generally classified into three categories: Long-day needs more than 12 hours daylight. Short-day grows with less than 12 hours of daylight. Day-neutral can be grown with success anywhere. Some of the Long-day varieties are Yellow Sweet Spanish, First Edition, Walla Walla and Buffalo.  Short-day varieties are Stuttgarter, White Bermuda, Red Burgundy and Southern Belle.  Day-Neutral varieties are Candy, Red Stockton and Super Star; 

PREPARING THE PLANTING SITE

Growing great onions, whether in the spring or fall, all starts with great soil which is well-drained, loose, and fertile. Compacted, rocky, or clay-heavy soil affects bulb development. Add aged manure or compost to the soil in the fall or early spring. Onion plants are heavy feeders and need constant nourishment to produce big bulbs. 

Select a location with full sun, where your onions won’t be shaded by other plants. At planting time, add about an inch of compost to the bottom of each row before planting. Or, dig a trench in the soil about 2 inches deep and 3 inches wide, and then fill the trench back in with about an inch of compost.

HOW TO PLANT

You can grow onions from transplants, sets, or seeds. Transplants, which are seedlings started in the current growing season and sold in bunches. They usually form good bulbs over a short period of time (65 days or less), but they’re subject to diseases and the choices are somewhat limited.  Sets are immature bulbs grown the previous year and offer the most limited choices but the easiest to plant, the earliest to harvest, and the least susceptible to diseases. However, sets are also more prone to bolting (sending up a flower stalk prematurely). When buying sets, look for 1/2-inch-diameter bulbs because they’re the least likely to bolt. Seeds offers the great advantage of a wide choices. Starting from seeds will take up to four months to mature. They will need to be started indoors. Onions like cool weather in the early part of their growth, so plant them in spring, except in mild-winter areas, where onions are grown as a fall or winter crop. Generally speaking, onions grow tops in cool weather and form bulbs when the weather warms. Plant onion seeds four to six weeks before the last average frost — or even earlier indoors or in a cold frame. When indoor seedlings are 2 to 3 inches tall, harden them off by exposing them to above-freezing night temperatures. Outdoors, sow seeds thickly in rows about 1/2 inch deep.  Thin seedlings to 1 inch apart, and thin again in four weeks to 6 inches apart.

For transplants or sets, use a dibble to make planting holes 2 inches deep and 4 to 6 inches apart. Use the closer spacing if you plan to harvest some young plants as green onions. For sets, open a furrow 2 inches deep and place the sets stem pointed end up 4 to 6 inches apart, and then fill in the furrow. One pound of sets will plant about a 50-foot-long row.

HOW TO CARE FOR ONIONS

Fertilize every few weeks with nitrogen to get big bulbs. Cease fertilizing when the onions push the soil away and the bulbing process has started. Do not put the soil back around the onions; the bulb needs to emerge above the soil. Generally, onion plants do not need consistent watering if mulch is used. About one inch of water per week (including rain water) is sufficient. If you want sweeter onions, water more.

PESTS/DISEASES

Thrips: tiny insects about as fat as a sewing needle. To control thrips take a dark piece of paper into the garden and knock the onion tops against it; if thrips are present, there will be tan-colored bodies on the paper. A couple of treatments with insecticidal soap kills them. Follow the package directions. Spray the plants twice, three days apart, and the thrips should disappear.

Onion Maggots: Cover your emerging onion crop with a fine mesh netting. Seal it by mounding soil around the edges. The onion maggot likes to lay its eggs at the base of plants, so the netting should prevent that. You should also keep mulch away because the insects like decaying organic matter, and make sure you completely harvest your onions as the season progresses. Onion maggots are usually only a problem in very rainy periods.

HARVEST/STORAGE

Once onion tops turn yellow, use the back of a rake to bend them over horizontally. This stops the sap from flowing to the stems and diverts the plant’s energy into maturing the bulb. A day or so later, when the tops turn brown, pull or dig the bulbs on a sunny day, and leave them to dry in the sun. Lay the tops of one row over the bulbs of another to help prevent sunscald.

When the outer skins are thoroughly dry, wipe off any soil and remove the tops—unless you intend to braid them. Store in a cool, dry place; hang braided onions or those kept in mesh bags in an airy spot. Such dried bulbs will keep for about four months to one year.

ONION SANDWICH RECIPE

This is just such a zestful sandwich as delighted that Yankee President, Calvin Coolidge. It is particularly good made with rye bread.

INGREDIENTS

1 large sweet onion

3 hard cooked eggs

2 small pickles

mayonnaise

1/2 teaspoon dry mustard

salt and pepper

INSTRUCTIONS

Chop the onion, eggs, and pickles fine and add enough mayonnaise to have a good spreading consistency, and mustard, salt, and pepper to taste. Spread lavishly. Serve with tomato wedges and ripe olives. Makes 6 servings.

While we all are practicing ‘social distancing’ and Halifax County buildings are still closed to the public due to COVID-19, if you have gardening questions, you can reach an Extension Master Gardener or Extension staff member.