IMPORTANT: Place Slips in Water or Moist Soil
Once your slips arrive in the mail or you've returned from picking them up in person, place them in a jar of water or a container of moist, loose potting soil until you are ready to plant. Warmth is more important than light. We recommend keeping them indoors in a sunny window.
Transplanting
Resist the urge to plant out your slips until the soil has warmed and nighttime lows are consistently above 10 degrees Celsius.
Choose a planting location with full sun. Loosen the soil to a minimum depth of one foot. If you have compacted or heavy soil, consider mounding the loosened soil into raised beds.
Amend the soil with compost or fertilizer such as bone meal, blood meal, or pelletized chicken manure.
Cover the area with clear plastic to help warm the soil. Black plastic also works, but I prefer vapour barrier that can be used year after year.
Plant your slips 12 inches apart in row and 36-48 inches between rows. Cut holes in the plastic and bury the slip up to its top three or four leaves.
Thoroughly water after transplanting and every 1-2 days for the first three weeks.
Growing
Once your sweet potato plants are established, they can be watered sparingly. If the summer is dry and hot, provide 1 inch/week. Let them dry out between waterings to avoid rot.
Every couple of weeks, lift the vines off the soil to stop rooting so that all of the energy goes into the tubers at the base of the plant.
Harvesting
Sweet potatoes must be left in the ground as long as possible to ensure they have time to size up.
Dig them up only when temperatures start regularly dipping below ten degrees at night but before there is any risk of hard frost (usually mid-September). To minimize damage during harvest, cut the vines a week before so the skin starts thickening.
If possible, harvest on a dry day. Use a digging fork or shovel to loosen the soil starting at least a foot away from each plant. Some sweet potatoes may be near the surface, so be careful!
If you plan to store your sweet potatoes over winter, they must be cured as soon as they are harvested.
Curing and Storage
To cure properly, sweet potatoes must be kept at 28 to 32 degrees Celsius and 85-90% humidity for the first 7-14 days. In the average home, this can be challenging. To get around this, try putting the sweet potatoes in paper bags inside plastic bags with a few holes punched in them (8-10 medium-sized sweets/bag). Then, place the bags in a small room or closet with a space heater or next to a wood stove. Leave a fan blowing on them to avoid rot.
Once cured, sweet potatoes will keep for months in the dark at room temperature. To prevent them from drying out, they can be left in paper and plastic bags. Do not store them below 12 degrees Celsius.
Sweet potatoes reach peak tastiness 8 weeks after curing, but with the right storage conditions, they’ll last well into the spring.
Grow Your Own Sweet Potato Slips!
Remember to keep a few small ones to grow your own slips from next year. Read our guide on slipping your own sweet potatoes.