All Purple

Family: Convolvulaceae Root Vegetable

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.

Light: Full SunMaturity: 90 DaysHabit: Vine

Planting schedules and alerts are optimized for Columbus (Zone 6b).

Crop Dates

Milestone	Date
Start Indoors	Direct Sow
Last Frost	Apr 25th
Transplant / Sow Outdoors	Jul 4th
Harvest Begins	Oct 2nd
Harvest Ends	Oct 16th

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

Culinary Notes

Chef's Note

All Purple earns its keep for that creamy, spoonable texture that forms without getting grainy, plus the skin-to-center color that doesn’t fade once it hits heat. Roast hard for browned edges, or puree it thick—its earthy-sweet profile plays beautifully with acid and smoke without turning cloying.

Best Uses

roasting until caramel-edged and custardy in the center
mashing for a velvet puree that stays deeply colored
thick wedges in a sheet-pan tray with peppery greens and a sharp vinaigrette
pickling-style preparation where the purple hue holds on the shelf

Flavor Profile

sweet, earthy flavor smooth, creamy interior inky-purple, mildly nutty finish

Kitchen Pairings

brown butter lime smoked paprika coconut milk black pepper goat cheese

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.