Yes, Plant Your Sprouted Onion: Complete Growing Guide

Yes, you can absolutely plant a sprouted onion and grow a new crop. This complete guide shows you exactly how to transform your kitchen sprouts into thriving onion plants with step-by-step instructions, realistic growth expectations, and professional gardening tips.

Have you discovered your stored onions have started sprouting? Don't toss them! Those green shoots emerging from your kitchen onions represent a perfect opportunity to grow fresh onions at home. Many home gardeners successfully rescue sprouted onions that would otherwise go to waste, turning them into productive plants with minimal effort.

Why Onions Sprout in Storage

Onions naturally enter dormancy after harvest, but when exposed to warm temperatures and humidity in your kitchen, they receive signals that spring has arrived. This triggers their biological imperative to grow. The sprouting process begins when the onion's internal energy reserves activate the embryonic plant within.

Sprouting Stage	Timeframe	What's Happening
Initial sprouting	1-2 weeks	Green shoots emerge from top; roots begin forming at base
Active growth	3-4 weeks	Shoots grow 2-4 inches; roots become visible
Advanced sprouting	5+ weeks	Onion begins to shrivel as energy transfers to new growth

Can You Plant a Sprouted Onion? The Complete Answer

The straightforward answer is yes—you can plant sprouted onions with excellent success rates. According to research from the University of California Agriculture and Natural Resources, onions that have begun sprouting actually have a head start on growth compared to planting from seeds or sets. The sprouting process indicates the onion is physiologically ready to grow, making it an ideal candidate for planting.

However, success depends on proper technique and timing. Onions that have just begun sprouting (with shoots under 2 inches) generally perform better than those that have been sprouting for weeks and have significantly depleted their energy reserves.

Step-by-Step: Planting Your Sprouted Onion

Step 1: Prepare Your Sprouted Onion

Carefully separate the green sprouts from the onion bulb if they've grown significantly. For onions with shorter sprouts (under 2 inches), plant them whole. If roots have already formed at the base, handle them gently to avoid damage. The Royal Horticultural Society recommends trimming excessively long sprouts to about 3 inches to reduce stress on the plant.

Step 2: Choose the Right Container or Garden Spot

Onions need well-draining soil and at least 6 hours of direct sunlight daily. Whether planting in your garden or a container:

• Use loose, fertile soil with good drainage
• Ensure containers are at least 6 inches deep
• Maintain soil pH between 6.0-7.5 for optimal growth

Step 3: Planting Technique

Plant your sprouted onion with the pointy end up, just below the soil surface. The top of the bulb should be visible above the soil line. Space plants 4-6 inches apart in rows 12-18 inches apart. Water thoroughly after planting, but avoid overwatering which can cause rot.

What to Expect: Growth Timeline

Understanding the realistic growth expectations prevents disappointment. Your sprouted onion won't produce a large bulb like commercial varieties, but you'll get valuable green onions and potentially small bulbs:

• Weeks 1-2: Existing sprouts continue growing; new roots establish
• Weeks 3-4: Green shoots thicken; you can begin harvesting scallion-style
• Weeks 5-8: Bulb begins forming; continue harvesting greens as needed
• Weeks 9-12: Small bulbs develop; harvest when tops begin falling over

When Planting Might Not Work: Important Limitations

While planting sprouted onions usually succeeds, certain conditions reduce your chances:

• Severely depleted bulbs: Onions that have sprouted for months and become soft or shriveled
• Diseased onions: Those showing mold, rot, or unusual discoloration
• Chemically treated onions: Commercial onions sometimes receive sprout inhibitors
• Wrong season: Planting in extreme heat or cold without protection

The USDA gardening guidelines note that while most sprouted onions can be planted, those stored in commercial settings may have been treated with growth inhibitors that reduce success rates by up to 40%.

Beyond Planting: Alternative Uses for Sprouted Onions

If planting isn't feasible or you want additional options:

• Regrow in water: Place the base in shallow water for continuous green onion production
• Use the greens: Sprouts make excellent chives substitute in recipes
• Compost: If the onion is too far gone, add it to your compost for nutrients

Maximizing Your Success: Pro Gardener Tips

Professional gardeners recommend these techniques to improve your sprouted onion results:

• Apply balanced fertilizer every 3-4 weeks to support growth
• Keep soil consistently moist but not soggy
• Remove flower stalks if they form to direct energy to bulb development
• Rotate planting location annually to prevent disease buildup

Remember that onions grown from sprouted kitchen bulbs typically produce smaller bulbs than those grown from proper onion sets. However, the green tops provide continuous harvest throughout the growing season.

Frequently Asked Questions

How long does it take for a sprouted onion to grow after planting?

You'll see continued growth within days of planting, with harvestable green onions available in 2-3 weeks. Small bulbs typically form in 8-12 weeks depending on variety and growing conditions.

Can I plant an onion that's completely sprouted and soft?

Onions that have become soft or mushy from excessive sprouting won't grow well. Choose onions that are still firm with just emerging sprouts for best results. Soft onions are better used for composting.

Do I need to remove the onion skin before planting?

No, leave the papery skin intact as it protects the bulb during planting. The new roots and shoots will naturally push through the skin as growth continues.

Will planting sprouted onions produce the same variety as the original?

Generally yes, but commercial onions are often hybrids that may not produce identical offspring. You'll get edible onions, but they might differ slightly in size, shape, or flavor from the original bulb.

Can I grow onions from sprouted onions indoors?

Yes, but they need at least 6 hours of direct sunlight or supplemental grow lights. Indoor-grown onions will produce greens continuously but typically won't form substantial bulbs without optimal light conditions.