How To Grow Sweet Potatoes

Plant Type: Annual
Name: Ipomoea batatas
Light: Full sun
Soil Type: Average to sandy loam
Soil Temperature: 75° – 85°
ph Range: 5.0 – 6.0
Watering: Keep evenly moist but not soggy
Plant (Payson): May 27 – warm soil – no chance of frost
Planting Method: Slips or seed potato
Germination: 8 – 12 days
Transplant: When soil is warm
Maturity (days): 100 – 125
Common Pests: Nematode, weevil, wireworm
Common Diseases: Black rot, soil rot, stem rot

OVERVIEW

Sweet potatoes are very frost tender. They want warm weather and a long growing season, therefore transplanting is the best method of planting in our area. They are grown from rooted cuttings, or slips. Slips can be purchased (easiest), or you can produce your own. Place the tuber in water (1/3 of tuber should be in water). When sprouts are 6 inches long, remove and place in soil where they can develop roots.

Plan on a large area as plants will grow to 3-4 square feet per plant. Add compost to the planting area.

Transplanting

It is best to do planting in ridges about 8 inches high so the soil is warmer and drainage is good.

Seed

Not applicable.

MULCHING

Black plastic can be used to help warm the soil.

WATERING

Water regularly, but don’t over water. Sweet potatoes don’t mind a little dryness. Don’t water at all 3-4 weeks before harvest to prevent tubers from splitting.

FERTILIZING

Apply all-purpose organic fertilizer or compost in the spring. Sweet potatoes are light feeders and do not need further feeding. Overfeeding produces more foliage and fewer potatoes.

Remove weeds until plants grow big enough to cover the planting bed.

Black rot, soil rot, stem rot.

Plant disease resistant varieties. If you have soil rot, roots will be brown and soft instead of firm and white. (Early signs are stunting & wilting of the plant.) Remove and destroy plant. DO NOT COMPOST.

BUGS

Nematodes – plant varieties that are resistant and fertilize with fish emulsion
Weevil – spray with pyrethrum (a natural insecticide made from dried flower heads)
Wireworm – trap wireworms with pieces of potato on wood spears

Sweet potatoes need at least 100 days of warmth to produce good tubers. Harvest just before the first frost in the fall. Some sources say to wait until the first frost, but others say frost can damage the tubers. To be safe, don’t wait for frost. The ridges you formed when planting should make harvesting easier as the tubers should be inside the ridges.

PRESERVING/STORING

Do not rinse tubers. Cure in the sun for several hours, then move to a heated room (85°-90° F for 7-10 days). After store at 50° F. Tubers should keep for several months. Sweet potatoes can also be canned and frozen.