How to Grow Inchelium Red Onion
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Inchelium Red Onion
Allium cepa
vegetableInchelium Red is a heirloom storage onion prized for its deep red-purple color, mild flavor, and exceptional keeping ability. This medium-sized variety produces globe-shaped bulbs with layers of crispy, thin skin and is ideal for fresh eating, storage, and processing. It's a long-day variety that originated from the Inchelium people of Washington State.
When should you plant Inchelium Red Onion in your zone?
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Example Inchelium Red Onion timeline · Pittsburgh, PA (Zone 6b)
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Plant Inchelium Red Onion
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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Harvest Inchelium Red Onion
Around Jul 26≈ 100 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Inchelium Red Onion dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 3-8; best in cooler climates with long day length
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Get my Inchelium Red Onion timeline →Growth Stages
Seedling/Set Establishment
2-3 weeksSmall green shoots emerge from onion sets or seeds. Fine, thin leaves develop. Root system establishes.
Keep soil consistently moist but not waterlogged. Thin seedlings to proper spacing if direct sown. Protect from heavy wind. No fertilizer needed initially if soil is well-amended.
Vegetative Growth
6-8 weeksPlants develop 4-6 green leaves per plant. Foliage grows upright and becomes more robust. Bulb development begins underground but not yet visible.
Maintain consistent watering (1-1.5 inches weekly). Apply balanced fertilizer every 3-4 weeks or use slow-release. Mulch lightly to retain moisture and suppress weeds. Monitor for onion maggots and thrips.
Bulb Development
4-6 weeksVisible bulb swelling occurs at soil surface. Plant foliage remains green and robust. Characteristic red-purple color begins showing through outer skin.
Continue consistent watering but avoid overwatering. Reduce nitrogen fertilizer; apply phosphorus-potassium blend if needed. Keep weeds controlled. Remove any weeds competing for moisture and nutrients.
Maturation and Hardening
3-4 weeksBulbs reach full size and color. Foliage begins to yellow and flop over naturally. Outer skin becomes papery and protective.
Reduce watering significantly—stop watering when foliage falls naturally. Do not break foliage over manually. Allow bulbs to cure in soil for 1-2 weeks after tops die back if weather permits.
Harvest and Storage
Harvest window: 1-2 weeksTops are completely dried and brown. Bulbs are firm, fully colored, and ready for curing. Skin is papery and protective.
Harvest when 75-80% of foliage has collapsed. Cure bulbs in cool, dry, well-ventilated area for 3-4 weeks before storage. Store in cool (40-50°F), dry conditions with good air circulation.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Use floating row covers on young plants. Rotate crops. Apply spinosad or neem oil at first sign. Remove affected plants immediately.
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Spray with neem oil or insecticidal soap weekly. Encourage beneficial insects. Remove heavily infested plants.
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Ensure excellent drainage. Avoid overhead watering. Practice crop rotation (don't plant alliums in same spot for 3+ years). Remove affected plants.
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Improve air circulation. Avoid overhead watering. Apply sulfur-based fungicide at first signs. Remove infected foliage.
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Cure bulbs thoroughly (3-4 weeks). Store in cool, dry conditions. Do not store damaged or soft bulbs. Ensure proper air circulation during storage.
Uses
Fresh eating and mild dishes
CulinaryInchelium Red onions are notably mild and sweet with low pungency, making them excellent for fresh eating, salads, and dishes where you want onion flavor without sharp bite. Their natural sweetness develops and intensifies when roasted or caramelized. [source]
Storage and preservation
CulinaryThis heirloom variety is prized for exceptional storage life (5-8 months under proper conditions) and maintains quality and flavor throughout winter. It's ideal for long-term pantry storage and processing into powders or dried onions. [source]
Natural dye and color
HouseholdThe deep red-purple skin and layers contain natural anthocyanin pigments that can be extracted and used as a natural dye for fabrics and food coloring. This makes Inchelium Red valuable for eco-conscious culinary and textile applications. [source]
Immune and cardiovascular support
MedicinalLike all onions, Inchelium Red contains quercetin and other polyphenols with antioxidant and anti-inflammatory properties. Traditional use includes supporting immune function, cardiovascular health, and digestion. [source]
Pollinator attraction
WildlifeIf left to bolt and flower, Inchelium Red onions produce delicate purple-pink flowers that attract bees and other beneficial pollinators to the garden. Allowing a few plants to flower supports pollinators and provides ornamental value. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
Harvest when 75-80% of foliage has naturally collapsed/fallen over—typically late July to August in northern climates. Do not break or bend foliage over artificially. Pull bulbs gently from soil. Leave attached foliage intact. Cure in warm (70-85°F), dry, shaded, well-ventilated location for 3-4 weeks until outer skin is papery and neck is tightened. Once cured, trim dried foliage to 1-2 inches. Store in cool (40-50°F), dry, well-ventilated conditions (mesh bags or loose in ventilated boxes). Can store 5-8 months with proper curing and storage.
Fun Facts
- 🌱 Inchelium Red is an heirloom variety specifically developed by and named after the Inchelium people, a Native American tribe in central Washington State, where it has been grown for generations and remains culturally significant.
- 🌱 This variety is a 'long-day onion' requiring 14+ hours of daylight to initiate bulb formation, making it ideally suited to northern climates (above 38°N latitude). It will not bulb reliably in southern regions.
- 🌱 Inchelium Red onions develop their characteristic deep red-purple color from natural anthocyanin pigments, the same compounds found in blueberries and red wine, which increase in concentration as the bulb matures and cures.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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