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Stuttgart

Allium cepa 'Stuttgart'

A classic German heirloom onion prized for its exceptional storage life and reliable performance in cool climates. This flat-topped yellow onion develops firm, dense bulbs with crisp white flesh and a pleasantly sharp flavor that mellows beautifully when cooked. Stuttgart's outstanding keeping quality makes it a favorite among gardeners who want to store their harvest through winter.

Harvest

110-120d

Days to harvest

📅

Sun

Full sun

☀️

Zones

5–10

USDA hardiness

🗺️

Height

12-18 inches

📏

Planting Timeline

Zone:

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Direct Sow

Harvest

Direct Sow

Harvest

Showing dates for Stuttgart in USDA Zone 7

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Zone Map

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Stuttgart · Zones 5–10

What grows well in Zone 7? →

Growing Details

Difficulty

Easy

Spacing4-6 inches

SoilWell-drained, fertile soil with good organic matter

pH6.0-7.0

Water1 inch per week, reduce as bulbs mature

SeasonCool season

FlavorSharp when raw, sweet and mild when cooked

ColorGolden yellow papery skin, white flesh

Size3-4 inches diameter, medium to large

Zone-by-Zone Planting Calendar

Zone	Indoor Start	Transplant	Direct Sow	Harvest
Zone 3	—	—	May – June	August – October
Zone 4	—	—	April – June	August – October
Zone 5	—	—	April – May	August – November
Zone 6	—	—	April – May	July – November
Zone 7	—	—	March – May	July – November
Zone 8	—	—	March – April	June – December
Zone 9	—	—	February – March	May – December
Zone 10	—	—	January – March	May – December

Complete Growing Guide

Light: Full sun (6 or more hours of direct sunlight a day). Soil: High Organic Matter, Loam (Silt), Sand. Soil pH: Alkaline (>8.0), Neutral (6.0-8.0). Drainage: Good Drainage, Moist. Height: 1 ft. 0 in. - 1 ft. 6 in.. Spread: 0 ft. 6 in. - 1 ft. 0 in.. Spacing: Less than 12 inches, 12 inches-3 feet. Maintenance: Medium. Regions: Coastal, Mountains, Piedmont.

Harvesting

Flowers wither and convert to bulblets

Type: Capsule.

Harvest time: Summer

Bloom time: Summer

Storage & Preservation

After curing, Stuttgart onions store exceptionally well in cool (32-40°F), dry conditions with good air circulation. Properly cured bulbs keep 6-8 months in a root cellar, unheated garage, or basement. Store in mesh bags, braided strings, or shallow boxes—never in plastic bags which trap moisture.

For shorter storage, keep Stuttgart onions at room temperature in a pantry for 2-3 months. Avoid storing near potatoes, which release gases that cause onions to sprout.

Stuttgart's firm texture makes it excellent for freezing when chopped—no blanching needed, though they'll lose crispness. These onions also dehydrate beautifully into flakes or powder. For longer preservation, Stuttgart's sharp flavor works well in pickled relishes and chutneys, maintaining good texture through the canning process.

History & Origin

Stuttgart onions originated in the fertile valleys surrounding Stuttgart, Germany, where they've been cultivated since the early 1800s. German farmers developed this variety specifically for its exceptional storage qualities—essential for surviving harsh European winters when fresh vegetables were scarce.

The variety gained popularity among German immigrants to America's Midwest in the mid-1800s, who brought seeds in their carefully guarded collections. Stuttgart became particularly valued in Wisconsin, Minnesota, and the Dakotas, where its cold tolerance and storage life made it indispensable for frontier families.

This heirloom represents classic German breeding priorities: reliability over flashiness, storage over immediate consumption, and adaptation to short, cool growing seasons. Unlike many modern hybrids bred for uniform appearance, Stuttgart was selected purely for performance—explaining its somewhat variable shape but consistently excellent keeping quality. Today, it remains largely unchanged from those original German strains, making it a true culinary and agricultural heritage variety.

Advantages

+Disease resistance: Black Walnut, Deer, Rabbits

Considerations

-Toxic: Low severity

Companion Plants

Plant Together

Carrots

Alliums repel carrot flies while carrots help break up soil for onion bulb development

Tomatoes

Onions deter tomato hornworms and aphids while improving tomato flavor

Cabbage

Onions repel cabbage worms, cabbage loopers, and flea beetles

Lettuce

Onions provide pest protection without competing for nutrients, complementary root depths

Peppers

Alliums deter aphids and spider mites that commonly attack pepper plants

Broccoli

Onions repel cabbage family pests including cabbage root fly and aphids

Roses

Onions help prevent black spot and repel aphids, Japanese beetles, and other rose pests

Strawberries

Onions deter slugs, aphids, and other soft-bodied pests that damage strawberry plants

Keep Apart

Beans

Onions can inhibit bean growth and nitrogen fixation by rhizobia bacteria

Peas

Alliums can stunt pea growth and interfere with their nitrogen-fixing capability

Asparagus

Onions may inhibit asparagus growth and can compete for similar soil nutrients

Nutrition Facts

Calories

40kcal(2%)

Protein

1.1g(2%)

Fiber

1.7g(6%)

Carbs

9.34g(3%)

Fat

0.1g(0%)

Vitamin C

7.4mg(8%)

Vitamin A

0mcg(0%)

Vitamin K

0.4mcg(0%)

Iron

0.21mg(1%)

Calcium

23mg(2%)

Potassium

146mg(3%)

Per 100g serving. % Daily Value based on 2,000 calorie diet. Source: USDA FoodData Central (FDC #170000)

Pests & Disease Resistance

Resistance

Good resistance to pink root and downy mildew

Common Pests

Onion maggot, thrips, aphids

Diseases

Purple blotch, downy mildew, white rot

Frequently Asked Questions

How long does Stuttgart onion take to grow from seed?▼

Stuttgart onions require 110-120 days from transplant to harvest. When starting from seed indoors, add another 10-12 weeks, making the total time from seed to harvest about 25-28 weeks. This long season is necessary for proper bulb development and the exceptional storage qualities Stuttgart is known for.

Can you grow Stuttgart onions in containers?▼

Yes, but choose containers at least 12 inches deep and 16 inches wide to accommodate Stuttgart's bulb development. Use well-draining potting mix and space plants 3-4 inches apart. Container-grown Stuttgart onions may be slightly smaller but will still develop good storage quality if given proper growing conditions.

What does Stuttgart onion taste like?▼

Stuttgart onions have a pleasantly sharp, pungent flavor when raw that's more intense than sweet onions but less harsh than some storage varieties. When cooked, they become sweet and mild with excellent caramelizing qualities. The flavor mellows significantly during storage, becoming more complex and less sharp over winter months.

When should I plant Stuttgart onion seeds?▼

Start Stuttgart seeds indoors 10-12 weeks before your last frost date. In most climates, this means late January to early March. Transplant outdoors when soil reaches 50°F and seedlings can handle light frost—typically 2-3 weeks before your last frost date.

Is Stuttgart onion good for beginners?▼

Stuttgart is excellent for beginners who can commit to the indoor seed starting process. Once transplanted, these onions are very forgiving and reliable. They tolerate cool weather well, resist many diseases, and clearly signal when they're ready to harvest. The main challenge is the long growing season requirement.

Stuttgart vs Yellow Globe onions - what's the difference?▼

Stuttgart has a distinctive flat-topped shape versus Yellow Globe's round bulbs, and significantly better storage life (6-8 months vs 3-4 months). Stuttgart offers better cold tolerance and disease resistance but requires a longer growing season. Yellow Globe tends to be more uniform in size and shape.