How long does it take to grow sweet potatoes?
Written by
Julia Anderson
Reviewed by
Prof. Martin Thorne, Ph.D.Sweet potatoes require 90-120 days from planting slips to harvest, depending on the variety chosen and local climate conditions. I've grown them both quickly and slowly with success; the clock starts when the slips are planted into warm ground. Early varieties are the best option in short-season areas.
Establishment Phase
- First 30 days: focus on root development
- Vines grow 1-2 inches daily after week 3
- Water daily during this critical period
- Protect from pests like cutworms
Tuber Initiation
- Days 40-60: tubers begin swelling
- Apply potassium-rich fertilizer at day 45
- Maintain consistent soil moisture
- Watch for leaf yellowing indicating stress
Bulking Phase
- Days 70-100: rapid tuber enlargement
- Tubers gain 80% of final weight
- Reduce watering after day 85
- Stop fertilizing completely
Several factors influence the speed of growth. Ensure the soil temperature remains above approximately 65°F. Growth slows down at night if the nights are cool. I use black plastic mulch in the spring, which warms the soil up quicker. Regular watering can make the difference between stunted growth and normal size. Too much nitrogen too quickly may also delay the formation of tubers.
Check for harvest readiness starting day 85. Carefully dig around the crown of the plant until you discover tubers that are about 1 ½ inches thick. I dig around one plant each week. Once the tops start to turn yellow, harvest them promptly. Don't wait for frost; it will kill the tubers and shorten the storage life.
Get a jump on the season in cooler climates. Use row covers for additional warmth in cooler temperatures. Start slips indoors 8 weeks early. I plant in raised beds covered with plastic mulch. In total, these methods will give you about an extra 3 weeks to grow. For best results, harvest before the first frost.
Read the full article: How to Grow Sweet Potatoes Successfully
