How to Grow Supima Cotton

Supima Cotton

Supima Cotton

Gossypium barbadense

vegetable

Supima cotton is a premium variety of cotton known for its extra-long staple fibers, superior softness, and durability compared to standard upland cotton. It produces fluffy white bolls containing the prized fibers used in high-end textiles and clothing. Supima requires a longer growing season and warmer climate than conventional cotton.

Growing Conditions

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Sun: Full sun, 8+ hours daily; requires intense sunlight for optimal fiber development
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Water: Moderate but consistent watering; requires 1-1.5 inches per week. Keep soil moist but not waterlogged. Reduce watering as bolls mature to concentrate sugars in fibers.
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Spacing: 24 inches
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Days to maturity: 180-210 days
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Planting depth: 1

Soil

Type: Well-draining loamy to sandy loam soil
pH: 6.0-7.0
Amendments:
Compost or aged manure Sulfur if pH is too high Phosphorus-rich fertilizer

Growing Zones

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Thrives in USDA zones 9-10, requiring 180-210 frost-free days

9a 9b 10a 10b

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Growth Stages

1

Seedling

2-3 weeks

Small plants with cotyledons (seed leaves) and emerging true leaves. Growth is slow initially in cool soil.

Keep soil consistently moist. Thin seedlings to proper spacing. Protect from cold; do not plant until soil reaches 60°F minimum.

2

Vegetative Growth

6-8 weeks

Rapid stem and leaf expansion; plant develops sturdy main stem with lateral branches and deeply lobed dark green leaves.

Maintain consistent watering and moderate nitrogen fertilization. Monitor for pests early. Support with stakes if in windy areas.

3

Flowering

4-8 weeks

Plant produces large, hibiscus-like flowers that are pale yellow on first day, then turn pink or red by second day before dropping.

Maintain steady watering and phosphorus-potassium balance. Reduce excess nitrogen to avoid excessive vegetative growth. Hand-pollinate if bee activity is low.

4

Fruit/Boll Development

4-6 weeks

Fertilized flowers develop into small green bolls (capsules) that gradually enlarge and mature over 4-5 weeks.

Decrease watering slightly to encourage fiber quality and maturation. Continue pest management. Maintain adequate potassium levels.

5

Boll Opening & Harvest

2-4 weeks

Mature bolls crack open to reveal fluffy white fibers (lint) with embedded seeds. Bolls typically open 3-4 weeks after reaching full size.

Stop watering once bolls begin opening. Harvest as bolls open to prevent fiber degradation and loss. Dry fiber thoroughly before storage.

Common Pests

  • Scout regularly for adult beetles and infested bolls; use pheromone traps; remove infested plant parts; consider beneficial insects or approved insecticides as last resort

  • Hand-pick larvae when populations are low; use Bacillus thuringiensis (Bt) spray; encourage parasitic wasps; monitor with pheromone traps

  • Increase humidity through irrigation; spray with water to dislodge; use sulfur or neem oil; release predatory mites

  • Use strong water spray; encourage natural predators (ladybugs, lacewings); apply insecticidal soap or neem oil if severe

  • Use yellow sticky traps; spray with horticultural oil or insecticidal soap; encourage parasitic wasps

Uses

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Cotton seed oil

Culinary

Cottonseeds yield edible oil rich in linoleic acid, used in cooking oils and food production. The oil is refined and commonly used in manufactured foods. [source]

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Premium textiles and apparel

Household

Supima cotton's extra-long staple fibers (1.375+ inches) create exceptionally soft, durable, and breathable fabrics preferred for high-end sheets, clothing, and luxury home goods. [source]

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Natural fiber for spinning and weaving

Craft

Gardeners can card and spin dried cotton fibers into yarn for weaving, textile arts, and historical fiber craft projects. [source]

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Gossypol alkaloid research

Medicinal

Cotton plants contain gossypol, a naturally occurring compound being studied for potential male contraceptive and anti-cancer properties in pharmaceutical research. [source]

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Pollinator nectar source

Wildlife

Cotton flowers provide nectar and pollen for bees and other pollinators, supporting beneficial insect populations in the garden. [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 by hand when bolls have fully opened and fibers are fluffy and white (typically 3-4 weeks after boll maturity). Wear gloves as opened bolls have sharp bract points. Pick every 2-3 days to maximize fiber quality and prevent weather damage. Dry harvested lint in shade at room temperature for 1-2 weeks before storage. Avoid compression and moisture during drying.

Fun Facts

  • 🌱 Supima cotton accounts for only 1-2% of global cotton production but commands premium prices due to its superior fiber length, strength, and softness compared to upland cotton.
  • 🌱 The name 'Supima' stands for 'Superior Pima,' derived from the Pima Native Americans of Arizona who cultivated a superior cotton variety for centuries.
  • 🌱 A single cotton plant can produce 1-2 pounds of raw cotton fiber (lint) per season, but it takes approximately 1,400 cotton bolls to make just one pound of processed cotton.

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