Dunnville Horticulture Society

Sweet Potatoes: It’s Harvest Time

Unlike Irish (white) potatoes, which save better if the vines are allowed to die down for three weeks before digging, it’s extremely important to dig sweet potatoes before the first frost.

Unfortunately, many gardeners do not grow this very easy, productive, and nutritious crop because of the perception they are a southern crop.

Because Southern Ontario days are longer than in the south, by planting sweet potatoes in early June and growing a 100-day variety, they are very mature (good size) by mid-September, although they will continue to grow until dug.

The 2019 crop has been superb – best ever!

Harvesting sweet potatoes is effective by following these suggestions:

  1. If the ends of the vines begin to yellow, digging can begin.
  2. Watch the weather reports and dig before the first frost.
  3. Dig on a warm, sunny day if this is possible.
  4. Use a spade fork and dig at least 40 cm away from the hill to prevent damaging a tuber as the roots spread widely.
  5. Remove the tubers carefully from the hill and gently rub off the soil.
  6. Do not wash the tubers. Handle carefully so the skin is not damaged.
  7. Allow the tubers to lie in the sun for the day, turning them once.
  8. Put them into trays/containers so tubers do not touch each other.
  9. Sweet potatoes are tastier if allowed to cure for two months:
  10. For the first two weeks, cure them at 27C with 80-90% humidity.
  11. Store through the winter at no lower than 12C (e.g. basement).
  12. NEVER put sweet potatoes in a refrigerator.
  13. Sweet potatoes are grown from rooted slips (not eyes).
  14. This can be done in February by placing a tuber in soil or water.
The spade fork is placed 40 cm from the vines. A green string is attached to indicate the top of the tuber. By placing it in a vase of water, slips will grow to root cuttings for the following year’s planting. This variety (Superior) has been grown continuously for over 45 years in the writer’s garden. —Haldimand Press photo by Lester C. Fretz.