What's the ideal planting time for sweet potatoes?
Written by
Benjamin Miller
Reviewed by
Prof. Samuel Fitzgerald, Ph.D.Determining when to plant sweet potatoes is a matter of timing for frost risk and warming soil. You want to wait until night temperatures remain above 50 °F (10 °C), and soil temperature is 65 °F (18 °C). I use a digital soil thermometer - I recorded an early planting last year when the soil was 60 °F (16 °C) and it delayed growth by three weeks.
Soil Readiness
- Test soil temperature at 4" (10 cm) depth
- Warm soil with black plastic mulch 2-3 weeks pre-planting
- Amend clay soils with sand for faster warming
- Avoid nitrogen-rich fertilizers pre-planting
Regional Timing Guide
- Northern zones: Transplant slips mid-May to early June
- Southern zones: Plant slips April-May for summer rains
- Coastal areas: Use raised beds to combat cool soils
- Mountain regions: Opt for short-season varieties like Georgia Jet
Frost Protection
- Use floating row covers for unexpected cold snaps
- Create microclimates with stone borders
- Water soil deeply before frost warnings
- Harvest early if hard frost threatens
Soil preparation is crucial for thermal regulation in the soil: I work in 1" (2.5 cm) of compost into my planting rows to stimulate microbial activity. Using compost, I measured a 5°F (2.8°C) faster soil temperature rise last year relative to adjacent untreated areas, and also achieved enhanced slip establishment rates.
Resist urges to plant early. Slips can survive a few nights of cold weather, but tubers don't grow well below 60°F (16°C). I noticed in 2022 that when I planted in early April, the roots were nearly 40% smaller than the roots grown from mid-May plantings. Use cold frames if you plan to extend the seasons by taking this approach.
Read the full article: How to Grow Sweet Potatoes: Complete Guide
