How to Grow Autumn Purple
Wikimedia Commons
Autumn Purple
Ipomoea batatas 'Autumn Purple'
vegetableAutumn Purple is a ornamental sweet potato variety prized for its striking deep purple foliage and trailing growth habit. It produces vibrant purple-fleshed tubers and is grown both for food production and ornamental landscape appeal. The plant thrives in warm climates and creates a dramatic visual display in gardens and containers.
When should you plant Autumn Purple in your zone?
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Example Autumn Purple timeline · Pittsburgh, PA (Zone 6b)
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Plant Autumn Purple
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 Autumn Purple
Around Aug 15≈ 120 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Autumn Purple dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 8-11; can be grown in zone 7 with protection
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Slip Development
3-4 weeksSprouted plantlets with small roots and 2-3 leaves develop from seed tubers or stored tubers placed in warm, moist conditions.
Keep soil consistently moist at 75-80°F. Provide bright indirect light. Slips are ready to transplant when 6-8 inches tall with developed root systems.
Establishment
2-3 weeksYoung transplants establish roots in garden soil, developing new leaf growth and beginning vine elongation.
Plant after last frost and soil reaches 60°F+ (ideally 70°F+). Water regularly to maintain moist soil. Mulch around base to retain moisture and warm soil. Monitor for transplant stress.
Vegetative Growth
6-8 weeksVigorous vine growth with rapidly expanding purple foliage, trailing stems reaching 3-6 feet or more, and extensive root system development underground.
Maintain consistent watering as vines spread. Apply balanced fertilizer monthly or use compost side-dressing. Provide trellising if vertical growth desired. Remove competing weeds.
Tuber Development
6-8 weeksUnderground tubers begin enlarging and accumulating starches and sugars. Purple skin and flesh become more pronounced. Foliage remains lush green to deep purple.
Reduce nitrogen fertilizer to encourage tuber bulking rather than excess vine growth. Water deeply but less frequently. Continue monitoring for pests. Avoid soil disturbance near vines.
Harvest Readiness
2-3 weeks before harvestTubers reach mature size with fully colored deep purple skin and flesh. Vines may begin to senesce in cool weather or decline naturally as day length shortens.
Stop watering 1-2 weeks before harvest to allow skin to cure and harden. Dig carefully to avoid bruising tubers. Harvest before first frost (tubers are frost-sensitive).
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Use yellow sticky traps; spray neem oil or insecticidal soap; encourage natural predators; resistant varieties when available
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Destroy infested tubers; practice crop rotation (avoid planting sweet potatoes in same area for 3+ years); use pheromone traps; plant early varieties to avoid peak weevil activity
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Row covers on young plants; neem oil or spinosad spray; reflective mulches; encourage predatory beetles
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Increase humidity with overhead irrigation; neem oil spray; insecticidal soap; remove heavily infested leaves
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Strong water spray to dislodge; insecticidal soap; neem oil; encourage ladybugs and parasitic wasps
Uses
Purple-fleshed tubers for cooking
CulinaryAutumn Purple sweet potato tubers are edible with a distinctive purple flesh and slightly earthy, sweet flavor. They can be baked, roasted, mashed, fried, or used in soups and side dishes. [source]
Purple leaves as edible greens
CulinaryYoung tender leaves and growing tips of Autumn Purple are edible and can be used in salads, sautéed, or cooked as greens with a mild, slightly nutty flavor. [source]
Anthocyanin-rich antioxidant food
MedicinalThe deep purple color indicates high anthocyanin content, which has antioxidant and anti-inflammatory properties. Purple sweet potatoes are studied for potential cardiovascular and metabolic health benefits. [source]
Decorative foliage and landscape plant
OrnamentalAutumn Purple is grown as an ornamental for its striking deep purple foliage, making it excellent for containers, hanging baskets, garden beds, and as a colorful ground cover or trailing plant. [source]
Pollinator and beneficial insect support
WildlifeThe small flowers of sweet potato vines attract bees and other pollinators. The dense foliage provides shelter for beneficial insects that help control garden pests. [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 after 120-150 days when tubers reach desired size, typically in fall before first frost (frost damages tubers). Dig carefully starting 12 inches from vine base, working outward to avoid cutting tubers. Cure harvested tubers at 75-80°F, 85-90% humidity for 7-10 days to harden skin and extend storage life. Store at 55-60°F in dark, well-ventilated conditions for up to 3-4 months.
Fun Facts
- 🌱 Autumn Purple's deep purple color comes from anthocyanins, the same beneficial compounds found in blueberries and dark grapes, making it a functional food with antioxidant properties.
- 🌱 Sweet potatoes are not related to regular potatoes; they belong to the Convolvulaceae (morning glory) family and are actually modified roots, not tubers like potatoes.
- 🌱 A single Autumn Purple vine can produce 3-8 mature tubers weighing 4-12 ounces each, with both purple foliage and purple flesh being visible throughout the growing season.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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