Red Japanese

Family: Convolvulaceae Root Vegetable

Velvety, coppery-orange flesh with a gentle sweetness greets you at harvest—“Red Japanese” sweet potatoes develop a smooth, satin texture that roasts to tender caramel notes and shines when mashed into silky purées.

The roots form with a distinctive reddish skin and a bright orange interior, offering reliable flavor and color for home gardeners who want dependable results in about 90 days. Grow “Red Japanese” for both its lush leafy greens and its richly hued roots—an all-season favorite for roasting and bold, color-forward sauces.

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	Apr 25th
Harvest Begins	Jul 24th
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)	70
Min Night Temp (°F)	55
Harden Off (days)	10

Culinary Notes

Chef's Note

“Red Japanese” sweet potatoes roast into a tender, satin-starchy interior with caramel-leaning sweetness—ideal when you want color and a smooth mouthfeel, not strings. Because the sweetness is gentle, it plays nicely with acidic hits and funkier smoke rather than cloying up with sugar-only flavors.

Best Uses

roast wedges until edges caramelize and centers stay buttery
silky mash or purée for an orange-pour texture (no gritty finish)
thick, color-forward purée sauces for chicken, pork, or grain bowls
bake-and-mash style fillings where sweetness needs balancing

Flavor Profile

gentle sweetness velvety, satin-starchy mouthfeel roasted caramel notes bright, lightly coppery finish

Kitchen Pairings

smoked paprika lime juice brown butter coconut milk black pepper maple

Frequently Asked Questions

What pest or disease most commonly affects Ipomoea batatas (Japanese red sweet potato), and what should I do?

Sweet potatoes commonly suffer from sweet potato weevil damage and root scarring, especially when slips are planted into infested soil or stressed plants are kept too dry. Use clean, certified slips; inspect slips for webbing/larvae before planting; rotate beds; and add row cover early so adults can’t lay eggs. If you see wilting that doesn’t recover, dig and discard affected plants to reduce spread of soilborne issues like rot.

How often should I water Ipomoea batatas during the main growing phase?

During active vine growth, keep the soil evenly moist but not soggy—aim for about 1 inch (2.5 cm) of water per week, adjusting for heat and rainfall. Once vines are established, water deeply only when the top 1–2 inches (2.5–5 cm) of soil dry out, because waterlogged soil promotes rot in the developing storage roots. In the final 2–3 weeks before harvest, water less to help roots cure and reduce cracking.

How can I tell when Ipomoea batatas is ready to harvest?

Harvest at about 90 days from planting (often when leaves begin to yellow and vines slow down), and wait for dry weather to reduce rot. Carefully dig a few roots with a fork—Japanese red sweet potatoes are ready when the skins are set and you can’t easily rub them off. After harvest, cure them in warm, humid conditions for 5–10 days to improve sweetness and storage quality.