Onion Sets Vs. Onion Plants VS SEEDS

Before You Plant Onions

It’s important to understand that some onion varieties may not grow well in your area. All onion bulbs develop in response to their exposure to the number of hours of sunlight in a day. Some onion varieties are long-day onions, appropriate for many growers in Zones 3, 4, 5 and 6. Some onions are short-day, appropriate for most growers in Zones 7, 8, 9 and 10. We also carry intermediate-day onions, which are suitable for most all growers, but ideal for Zones 5, 6 and 7.

When choosing onion varieties, it is crucial to consider your specific area as some may not thrive in certain regions. The development of onion bulbs is directly influenced by the amount of sunlight they receive each day.

Short-day onions need 10-12 hours of light each day to start bulbing. They are best grown in southern climate zones. Grow short-day onions if you like them sweet—they have a high sugar content, but also a high water content, which makes them better for immediate use and not as ideal for long-term storage. If you make a mistake and buy long-day varieties, you won’t get full-sized onions but you will get a nice crop of tasty green-onion tops!

Long-day onions begin bulbing when days are 14-16 hours long. This is the type to choose if you live in the northern half of the U. S. Long-days are lower in sugar content and higher in sulphur, which lends them to much longer storage times and better canning results. (Of course, you can also use them as soon as you harvest them.

Intermediate Day (or Day Neutral) Onions

This group includes varieties that begin the bulbing process when daylengths reach 12-14 hours. Ideal in latitudes 32 to 42 degrees, the range of these onions overlaps that of short- and long-day onions. They perform well through much of the United States, except for the far south. Intermediate day onion varieties tend to be very sweet.

Onion Sets are small, dry onion bulbs that have been grown the previous year. They are the easiest for many gardeners to grow.

onion Sets are dormant bulbs that can be planted directly into the ground. Onion sets should be planted 1 to 2 inches deep and 2 to 3 inches apart. Then, once the plants begin to grow, thin them to 3 to 4 inches apart. Plants thinned from the row to create room can be used as green onions. To ensure proper growth of your onion sets, it is recommended to plant them directly into the ground. Plant the sets 1 to 2 inches deep and space them 2 to 3 inches apart.

ONION PLANTS

 plants are best. For large, firm bulbs,  They were produced from seed in the year  Dig a shallow trench, and lay the onion plants against one side of the trench about an inch deep and four inches apart. Cover with soil and irrigate.

Onion Seeds 

The advantage of growing from onion seed is that you open yourself up to a wide range of varieties. Although you can direct seed into the ground in warmer climates, onion seeds take a long time to grow and mature. To make the most of your onion growing experience, consider starting from onion seed. This will give you access to a diverse array of onion varieties to choose from.

That means for warmer climates, they need to be go in the ground in the fall or late winter. For northern climates, start seeds indoors 10 weeks prior to moving outside to transplant. In essence, this is the process of planting onion transplants or seedlings. And, it is a much better way to go when planting from seed.

Onions are cool-season vegetables that are grown mainly for the flavor they add to other foods. In areas where freezing temperatures are rare, they are grown as a winter crop, while in other areas they can be planted in the spring. Onions (Allium cepa) begin to form bulbs based on day length. Growing in zones 5 to 10, onions can be started from either sets or transplants. You'll find advantages to each.

The common onion (Allium cepa) is a biennial bulb that is closely related to garlic (A. sativum), shallots (A. ascalonicum), and chives (A. schoenoprasum). Onions have hollow, tubular, blue-green leaves that emerge from a bulb, which is actually a modified leaf structure with many layers. A shallow network of roots extend from the bottom of the bulb, and the bulb might push partially above ground as the plant matures. Onions are a biennial bulb closely related to garlic, shallots, and chives. They have hollow, tubular, blue-green leaves that emerge from a bulb, which is a modified leaf structure with multiple layers.

Onions should be planted in the spring, and they have a moderate growth rate. They can be planted from seeds, transplants (seedlings that have just sprouted), or sets (small onion bulbs that are about to begin their second, final year of growth). Note that onions are toxic to pets due to their chemical compounds, so be mindful about where you plant them.1

How to Plant Onions

When to Plant

Plant onions in the spring when the ground thaws and the temperature remains above 28 degrees Fahrenheit. Sunny spots with loose soil and a neutral pH are best. Leave at least 6 inches between each plant, spacing onion rows about 1 foot apart to allow room for the maturing plants to spread.

Onion seeds are usually started indoors approximately six weeks prior to the outdoor soil temperature being around 50 degrees Fahrenheit. If you're starting with seedlings, plant them outside when the soil temperature is around 50 degrees Fahrenheit as well. 

To ensure successful growth of onion seeds, it is recommended to start them indoors about six weeks before the outdoor soil temperature reaches approximately 50 degrees Fahrenheit. Similarly, if you have seedlings, it is advisable to transplant them outside when the soil temperature is around 50 degrees Fahrenheit.

It’s also possible to plant in the fall in warmer climates. The onions will stay dormant over the winter and then continue to grow in the spring.

Selecting a Planting Site

Choose a sunny spot with loose soil. Compacted or rocky soil will hinder bulb growth. Also, avoid planting where other Allium species have been in the past few years. Pests and diseases that target the plants can linger in the soil. Container growth is also an option if you don't have proper garden conditions.

Spacing, Depth, and Support

To plant onion sets, press them into the soil so just the top is visible. Space the sets roughly 4 inches apart, and space rows 12 to 18 inches apart. Once the sets are in the ground, leave them alone; do not hill soil up around them.  The sets are supposed to peek out of the ground at all times.

Plant seeds only about 1/4 inch deep. And thin seedlings to around 4 inches apart also in rows that are 12 to 18 inches apart. A support structure generally won't be necessary.

Onion Plant Care Proper watering techniques

Light

Onions need full sun—at least six hours of direct sunlight per day—to grow properly. With onions, the more sunlight the better.

Soil

Proper soil is the key element to growing onions successfully. The soil needs to be extremely well-drained—even sandy—and it should have lots of organic matter. A loose loam will work well. And a soil pH that hovers around neutral to slightly acidic is best.

Water

Onions need regular water to support the swelling of the bulbs. Give them 1 inch of water per week. But don't overwater or allow the bulbs to sit in soggy soil because this can lead to bulb rot. A light layer of mulch can help to retain soil moisture.

Temperature and Humidity

Onion seeds need temperatures of at least 40 degrees Fahrenheit to germinate. The optimal growing conditions for onions are between 68 to 77 degrees Fahrenheit. Humidity typically isn’t an issue as long as soil moisture needs are met.

Fertilizer

Onions are fairly heavy feeders. Fertilize them every few weeks with a high-nitrogen fertilizer to support leaf growth, which will produce big bulbs.  Once the soil begins to crack around where the bulb is forming, the foliage growing cycle is complete and no further application of fertilizer is required. To ensure optimal growth, it is recommended to fertilize onions every few weeks with a high-nitrogen fertilizer. This will support leaf growth and result in the development of larger bulbs. It is important to follow the instructions provided on the product label for the correct amount to use.

Pollination

Gardeners usually grow onions as annuals and harvest before flower stalks.

FAQ

• How long does it take to grow a  onion?

  Red onions take anywhere from 90 to 120 days to reach maturity depending on the variety and whether they're planted from seed Plants or onion sets.

• Can you grow a onion from another onion?

  Yes. You can plant the root end of a mature onion in soil and harvest the green tops. You can also remove and replant the new shoots from an onion that has sprouted and plant those in your garden to grow new onion plants.

• When should you plant onions?

   onion sets should be planted as soon as the ground can be worked in early spring. Red onion seeds should be started indoors eight to ten weeks before your region's last frost date. Red onions can also be planted in fall four to six weeks before your first frost date.