How to Plant Autumn Onion Sets for a Bountiful Spring Harvest

As gardeners we have come to think of autumn as the end of the gardening season. It is anything but the end. All of you, fall means the start of gardening season for next year. There’s no better way to start the season than by planting onions, shallots, and elephant garlic.

Today, we are going to discuss onions, a vegetable that can or should be planted in the fall. Onions can be planted in the fall for a mid-summer crop. They can also be planted in the spring for a late autumn or early winter crop.

Onions are one of the most important home garden crops available for cultivation today. If planted at the proper time of year, they are easy to grow. Onions are classified as long day, short day and midday varieties. The levels of these groups show how much daily sunlight the onion needs to grow into a big bulb.

Short day onions require a short winter day. Midday onions are flexible andcan tolerate a range of day length. Long day onions need the long days of summer to produce bulbs.

Most people who garden at home should choose midday onion types. However, southern gardeners who plant onion sets in the fall can choose either short day or midday onion types.

Onions are sold as seed or sets. Sets are baby onions and give you a head start on the season. For most gardeners, we recommend planting sets. If you want to plant seeds, you should do so as soon as the ground can be worked in the spring for a late fall crop or early in the middle of summer for the following spring crop.

Today’s home gardeners need to amend the soil where they are planting onions with potash and phosphate. There are organic sources for both of these nutrients. Some lime will also make the onions sweeter. People who garden often forget to add potash and phosphate to the soil, and when they plant onions, they sometimes plant the sets too deeply. Onion sets should be planted no more than 2 inches deep. In places where it freezes and thaws a lot, we suggest that you cover your plants with 4 inches of straw (not hay) in the winter.

Onions should be planted twice a year – once in the fall and once in the spring. The fall-planted onions can be harvested throughout the summer and early fall. The spring-planted onions can be harvested throughout the fall and early winter.

Red onions are arguably one of the most beautiful vegetables. On the outside, the skins can be a beautiful burgundy wine color. As you peel off the layers, the color changes from true purple to fuchsia to lavender are beautiful and will inspire any cook. The fact that they are among the sweetest onion types makes them a good choice for growing in a home garden. BUT, red onions are also the most problematic members of the onion family. Maybe eons ago their beauty and sweetness went to their heads – who knows.

What we do know is that red onions do not store well. They rot quickly and completely. If you want to grow red onions, you should plant them next to yellow onions, which will store well.

Try some red onions in your garden, but consume them quickly after harvest. These sweet beauties don’t last long.

White onions are the “Middle-of-the-Roaders” in the onion family. They are not as sweet as the reds, but they store for much longer than the reds. White onions are great for cooking and pickling, and as you can see from the picture, they are also beautiful in their own way.

Add lime to the soil before you plant the sets if you want your onions to be as sweet as possible.

Yellow Onions are the “Workhorses” of the onion family. They are sweet, but not as sweet as red or white grapes. They keep for a very long time. Many times, they can last six months or longer if kept in a cool, dry place where air can flow.

Yellow onions are the strongest of all the onion types and are great for cooking, either fresh or pickled.

There are a few things you need to keep in mind whether you plant yellow, white, or red flowers.

First, today’s home gardeners need to amend the soil where they are planting onions with potash and phosphate. There are organic sources for both ofthese nutrients.

Second, do not plant onion sets more than 2 inches deep. Leave 4-6 inches of space between sets and 6-8 inches between rows. In places where it freezes and thaws a lot, we suggest that you cover your plants with 4 inches of straw (not hay) in the winter.

If you want your onions to be as sweet as possible, add lime to the soil before you plant the sets.

Fourth, you should plant onions twice a year, once in the fall and once in the spring. The fall-planted onions can be harvested throughout the summer and early fall. The spring-planted onions can be harvested throughout the fall and early winter.

Having conversations with my gardening clients about when to plant onions is one of the most interesting things I do. A huge number of customers have told me that where they live in the fall it is too cold to plant onions. This is true in Hardiness Zones 1 and 2, and sometimes in Hardiness Zone 3. But in Hardiness Zones 4 through 10, you can and should plant onions in the fall. It is not an overstatement to profess that onions do best when planted in the fall. For the past 28 years, I’ve planted onions in the fall in a real Hardiness Zone 4 area where the wind blows nonstop all winter. I have never had an onion crop fail.

When you first start growing onions, I think you should start with yellow ones. But I think you will be thrilled with the results next spring no matter what kind of onions you start with.

All of the onion varieties discussed in this newsletter are available on ourwebsite. Please visit our website to purchase onion sets for your garden.

Today, August 31, 2019, is the first day of Labor Day Weekend. Also, our series on planting heirloom flower bulbs in the fall starts. Some of the most enchanting stories about gardening originated with the flower bulbs that we plant in autumn. Don’t miss a single installment of our series on heirloom flower bulbs for fall planting.

Onions are a versatile vegetable that adds flavor to many savory dishes. While onions can be grown from seeds sown in spring, planting onion sets in autumn offers several advantages. Onion sets are miniature onion bulbs that allow you to get a head start on next year’s onion crop. Follow this complete guide to learn when and how to plant autumn onion sets for big, healthy bulbs come spring.

What are Onion Sets?

Onion sets are essentially baby onion bulbs They are grown specifically for autumn planting rather than consumption. Onion sets form petite bulbs just 1/2 to 1 inch wide, compared to a mature onion bulb which can grow to over 4 inches across

These tiny bulbs are planted out in fall and overwinter in the garden Then they develop into full size onions the following spring and summer Each planted set yields one large onion bulb at maturity.

Reasons to Plant Onion Sets in Fall

Growing onions from sets planted in autumn offers several advantages over sowing seeds in spring:

Earlier harvest – Sets get a head start in fall so you harvest bigger bulbs weeks earlier next year

Less bolting – Cool weather reduces risk of premature flowering (bolting)
Less weed competition – Onion sets get established before spring weeds germinate
Wider variety – Sets allow growing specialty varieties not available as seeds

Higher success rate – Sets are less prone to soil-borne diseases than onion seeds

For northern gardeners, onion sets bridge the gap between fall and spring planting seasons.

When to Plant Onion Sets

Onion sets should be planted in the garden 6-8 weeks before the ground freezes in winter. This timing varies by growing zone, but generally falls between late September and late November.

Zones 3-4: Late September to mid October

Zones 5-6: Mid October to early November
Zones 7-8: Early to late November

Ideally, plant sets when daytime highs are 60-70°F and night temps are averaging 45-55°F. Avoid planting too late when ground may freeze.

Selecting Onion Set Varieties

Onion sets come in a rainbow of bulb colors including yellow, white, and red. Popular varieties include:

Yellow – Copra, Stuttgarter
White – Evergreen White Bunching, Walla Walla
Red – Red Wethersfield, Red Burgundy

Choose early maturing, long day varieties adapted to your region. Talk to local gardeners or your local extension office for the best performersets in your area.

Where to Buy Onion Sets

Look for onion sets bundled in mesh bags at local garden centers in fall. Most sets are a variety called Stuttgarter. Specialty catalogs and online seed shops offer a wider selection.

When buying sets, look for:

Firm, compact bulbs without mold, shriveling, or sprouting
Similar bulb size in a package for even growth
Correct variety and quantity for planned planting

Avoid sets with green sprouts as they may bolt before forming bulbs.

How to Plant Onion Sets in Fall

To get your autumn planted onion sets off to the best start, follow these simple planting steps:

Site Selection

Choose a planting area with full sun in fertile, well-draining soil. Avoid heavy clay or areas prone to standing water.

Soil Preparation

Work aged compost or well-rotted manure into the top 6 inches of soil to enrich and loosen the earth. Rake smooth.

Make Furrows

Use a hoe to create 2-3 inch deep furrows spaced 9-12 inches apart across the planting area. Wider rows give onions room to grow.

Set Bulbs

Place onion sets into furrows 4-6 inches apart, pointed end up. Push sets gently into soil so just the tip shows. Cover sets with surrounding soil.

Water & Mulch

Water furrows after planting. Add a 2 inch layer of straw or shredded leaves to conserve moisture and insulate bulbs.

Dig a trench that is two inches deep and a few inches wide. Set the bulbs in the compost with the pointy end facing up. This will ensure the bulb will sprout quickly through the soil. Space the bulbs 4 to 6 inches apart.

Proper autumn planting sets your onions up for vigorous root growth before winter dormancy.

Growing Onions Sets Through Winter

Onion sets require little care once planted in fall. Here are tips for success:

Water plants if autumn turns dry to establish roots before winter
Mulch over sets with straw or leaves after soil freezes to insulate bulbs from temperature swings
Check that mulch remains in place throughout winter

Avoid walking on planted areas or working soil when ground is frozen
Remove mulch in early spring so plants can emerge as weather warms

The small bulbs remain dormant through winter. Onion sets resume growing when soil temperatures rise above 40°F in spring.

Onion Care in Spring

As soon as soil thaws in early spring, begin caring for actively growing plants:

Pull back any remaining winter mulch
Weed around onion plants while young to minimize competition
Side dress each row with balanced organic fertilizer

Water weekly if rainfall is lacking, avoiding waterlogged soil
Monitor for insect pests and disease; treat organically if found
Hill soil around the base as bulbs enlarge to stabilize plants

With proper spring care, onions will be ready to harvest up to 4 weeks earlier than spring sown plants.

When to Harvest Onion Sets

Onions grown from sets are ready to harvest roughly 100-120 days after planting. This means you can harvest bulbs as early as May or June, depending on your climate.

Plants are mature when the tops begin to fall over and brown. Stop watering at this point to hasten ripening. Then pull up bulbs and allow them to cure in a warm, dry spot for 1-2 weeks. Trim tops and store cured onions in a cool pantry or cellar. Autumn planted onions store beautifully all the way until the next year’s crop comes in!

Storing and Saving Onion Sets

Cured bulbs keep for months in a cool, dark location. Check stored onions periodically and use up any that show signs of sprouting or spoilage. Saving your own onion sets is also an option:

Select your largest, healthiest bulbs from this year’s harvest

Remove the outer papery layers and stalks
Allow bulbs to cure for another 2 weeks
Place cured bulbs in an open container in a cool (40-50°F), dry location

Sets will keep for 6-10 months; discard any that show signs of rot
Replant best bulbs the following autumn

With proper curing and storage, you can perpetuate your own onion sets season after season.

Troubleshooting Onion Sets

Onion sets are quite hardy but occasionally issues may arise:

Flower stalk forms before bulb matures = Bolting, caused by cold weather or small sets. Remove flower stalk to redirect energy to bulb growth.
Plants fall over early in season = Sets planted too shallowly. Hill up soil 1-2 inches around bulbs to stabilize.
Stunted, pale plants = Nutrient deficiency from unamended soil. Side dress with balanced organic fertilizer.

Distorted or rotten bulbs = Disease like basal rot. Avoid planting sets in same soil year after year.
Holes in leaves = Onion thrips. Spray with insecticidal soap.

With care, you can achieve a bountiful onion set harvest!

Enjoying the Benefits of Onion Sets

Growing onions from autumn planted sets offers many advantages to the home gardener:

Earlier harvest extends enjoyment of fresh onions
Wider variety allows growing specialty onions not sold as seeds
Sets adapt well to a wide range of climates

Compact bulbs efficiently use limited garden space
Reduced weed and disease pressure improves success
Saving your own sets perpetuates the annual harvest

With proper timing and care, onion sets yield delicious, long-storing bulbs from an easy fall planting. Give this homesteading classic a try – you may find planting onion sets in autumn becomes a yearly tradition!

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