How to Grow Bicolor Iroquois Corn
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Bicolor Iroquois Corn
Zea mays
vegetableBicolor Iroquois is a classic sweet corn variety featuring kernels that are a mix of yellow and white on the same cob, offering a tender, sweet flavor. This mid-season hybrid reaches 6-7 feet tall and produces two ears per stalk with excellent eating quality. It's beloved by home gardeners for its traditional taste and attractive appearance.
When should you plant Bicolor Iroquois Corn in your zone?
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Example Bicolor Iroquois Corn timeline · Pittsburgh, PA (Zone 6b)
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Plant Bicolor Iroquois Corn
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 Bicolor Iroquois Corn
Around Jul 1≈ 75 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Bicolor Iroquois Corn dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 3-9, best in zones 5-8
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Seedling
10-14 daysEmerging shoots with first true leaves visible; plants are 2-4 inches tall
Keep soil consistently moist. Thin seedlings if needed to proper spacing. Watch for birds and cutworms.
Vegetative Growth
20-30 daysRapid leaf development; plants grow 12-24 inches tall with 6-8 visible leaves
Apply nitrogen fertilizer when plants are 6-8 inches tall. Water deeply and consistently. Begin side-dressing with compost or balanced fertilizer.
Tasseling & Silking
10-15 daysMale tassel emerges from plant top; silks appear from developing ears; plants 4-6 feet tall
This is the critical growth phase. Ensure consistent moisture (1-2 inches per week). Apply final nitrogen dose. Pollination depends on proper hydration and warm temperatures (60-90°F ideal).
Grain Fill
25-35 daysSilks dry and brown; kernels develop from milky to fully mature; ears become plump and heavy
Maintain steady watering even as silks dry. Kernels need 20-30 days to fully mature after pollination. Continue supporting stalks in windy areas.
Harvest Readiness
2-3 days (harvest window is narrow)Kernels are full-sized and creamy; husks are fully green; silks are dark brown and papery
Check ear maturity by puncturing a kernel with a thumbnail—milky juice indicates peak sweetness. Harvest immediately when ready for best flavor. Do not delay.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Bt (Bacillus thuringiensis) spray when silks emerge; remove affected ears; plant early or late to avoid peak populations
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Bt spray at whorl and tassel stage; remove and destroy infested plant material; rotate plantings
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Inspect regularly; hand-pick larvae; Bt or spinosad sprays; encourage natural predators
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Strong water spray to dislodge; neem oil; insecticidal soap; encourage ladybugs and lacewings
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Hand-pick early morning; row covers on young plants; neem oil; avoid overwatering which attracts them
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Collars around seedling stems; diatomaceous earth; encourage ground beetles; avoid excess mulch near stem
Uses
Fresh eating and cooking
CulinaryBicolor Iroquois corn is prized for eating fresh off the cob, boiled, grilled, or roasted. The balanced sweetness and tender kernels make it ideal for summer meals and corn salads. [source]
Freezing and preservation
CulinaryKernels can be cut from the cob and frozen for winter use, maintaining quality for 8-12 months when properly blanched and stored. [source]
Ornamental display
HouseholdThe distinctive bicolor kernels make dried ears attractive for fall decorations, dried corn wreaths, and harvest arrangements. [source]
Corn chowder and soups
CulinaryThe tender, sweet kernels are excellent in cream-based chowders, bisques, and vegetable soups where flavor is paramount. [source]
Wildlife food source
WildlifeLeft unharvested ears provide food for birds and small mammals in fall, supporting local wildlife populations. [source]
Harvest Tips
Harvest when silks are dark brown and kernels produce milky juice when punctured with thumbnail (typically 20 days after silking). Ears are ready when they feel full and kernels don't dent easily. Pick in early morning for best sweetness. Grip the ear firmly and twist downward sharply. Use immediately or refrigerate—sweetness declines rapidly after harvest. For bicolor varieties especially, harvest at peak ripeness for optimal yellow-white kernel color contrast.
Fun Facts
- 🌱 Bicolor corn kernels result from a genetic interaction where yellow endosperm is partially masked by white aleurone, creating the striking two-tone appearance that makes Iroquois so visually distinctive.
- 🌱 Corn silk is actually the stigma (female reproductive organ) of the corn plant—each silk strand connects to a single kernel on the cob, which is why more silks mean fuller ears.
- 🌱 Sweet corn is uniquely different from field corn because of mutations that prevent starch conversion to sugar; Bicolor Iroquois retains this recessive gene that keeps kernels sweet rather than starchy.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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