All Purple

Sweet Potato

Zone 8b Save Garden

🌱 90d to harvest Vine

Velvety, inky-purple flesh and skin create a striking first impression—All Purple sweet potatoes deliver a sweet, earthy flavor w…

Crop Dates

Milestone	Date
Start Indoors	Direct Sow
Last Frost	Mar 23rd
Transplant / Sow Outdoors	Jun 1st
Harvest Begins	Aug 30th
Harvest Ends	Nov 12th

Crop Details

Trait	Value
Days to Maturity	90
Sun Requirements	Full Sun
Growth Habit	Vine
Support Needed	Trellis
Planting Depth	Normal
Germination Temp (°F)	75
Min Soil Temp (°F)	65
Min Night Temp (°F)	55
Harden Off (days)	10

Recommended Companions

Genovese Compact Improved Basil

Lemon Mrs. Burns Basil

Frequently Asked Questions

Why are my purple tubers/roots getting soft spots or fuzzy growth—what disease is it and what should I do?

On all-purple tubers/roots, soft, sunken areas with gray/white fuzzy growth are often late-season rots (commonly driven by high humidity and wet soil). Pull and discard affected plants promptly, then improve drainage and stop overhead watering; water only at the soil line. If you catch it early, remove diseased tissue and keep the planting area evenly drier to slow further spread.

During the main growing phase, how often should I water all purple to keep tubers/roots from splitting or staying small?

From establishment through bulking, water deeply about 1–2 times per week so the top 6 inches of soil stays evenly moist but not soggy. If your soil is sandy, you may need more frequent watering; if it’s clay, reduce frequency to avoid waterlogging. When plants start to mature near day ~80–90, cut back to lighter waterings to help the all-purple roots size up without staying wet too long.

How can I tell when all purple is ready to harvest at around 90 days?

Harvest when foliage begins yellowing and the tops start to fall over, usually around day 90 for best size. For a quick check, gently dig near the edge of the plant and look for roots/tubers reaching their full color and a firm, mature feel. Avoid harvesting right after heavy rain—let soil dry slightly so skins don’t smear and tubers/roots store better.

Velvety, inky-purple flesh and skin create a striking first impression—All Purple sweet potatoes deliver a sweet, earthy flavor with a smooth, creamy texture when cooked. The uniform, deep-purple roots are prized for their rich color and versatility, shining in roasted preparations and also holding their hue beautifully for mashing, purées, and pickling-style uses. With about 90 days to maturity, this variety is an inspiring choice for gardeners who want both standout color and dependable harvest quality.

Sowing Tips

Transplant Conditions

Wait until soil reaches 65°F and nights stay above 55°F before moving outdoors. Harden off for 10 days first.

Direct Sow Preferred

Sensitive roots — does not transplant well. If starting indoors, use biodegradable pots and disturb roots as little as possible when moving outdoors.

Expert Note

For best purple-fleshed flavor, use slips/cuttings and wait until soil is fully warm before planting; keep evenly moist until vines establish, then water less to encourage tuber sizing.