How to Grow and Harvest Sweet Potatoes in Your Garden

Sweet potatoes grow best in warm soil, ideally with a soil temperature between 75 degrees and 95 degrees Fahrenheit—the growing season will vary depending on your climate. If your area has cold winters and mild summers, start your sweet potatoes indoors up to eight weeks before the last spring frost date. In the northern United States, this usually means starting your sweet potatoes indoors in late winter or early spring. If your area has very hot summers and mild winters, plant sweet potatoes outdoors in mid-to-late spring, once the weather is warm.

Sweet potatoes have a long life cycle in comparison to other garden fruits and vegetables—sweet potatoes typically take between 100 and 150 days to reach harvest. Since the growing period is so long, take note of the number of days of appropriate warm weather you have in your climate’s growing season, and plan accordingly. If your summers aren’t long enough, you may need to start your sweet potatoes indoors.

While many garden vegetables are grown from seeds, sweet potatoes are grown vegetatively, meaning that new sprouts, or slips, will grow from the nodes on mature produce.

1. Buy seed sweet potatoes. To grow sweet potatoes, you’ll need seed sweet potatoes or pieces of sweet potatoes covered in “eyes”—puckered spots on mature potatoes that readily sprout slips—which you can plant to grow your crop. Purchase seed sweet potatoes three months before you plan to plant, that way you have adequate time to start the slips before putting them in the ground. Avoid selecting grocery-store produce for your seed potatoes, if possible; they may be treated with inhibitors that prevent sprouting.
2. Start your sweet potato slips. Around three months (or 90 days) before planting, place your seed sweet potatoes in a warm, sunny room (around 65 degrees Fahrenheit) to encourage hardy sprouting. Keep them moist as the new slips begin to grow.
3. Plant your slips indoors. When your new plants are between three and five inches tall, cut them off of the sweet potato at the base and plant them in potting soil. (Keep new plants indoors, if the weather in your area isn’t warm enough).

After planting your sweet potatoes, you’ll need to weed, water, and control pests to help your crop thrive.

• Keep soil moist. Sweet potato plants are tropical plants, meaning they need warm, moist soil to thrive. Watering the planting area consistently can stop your potatoes from cracking or turning knobby.
• Keep sweet potatoes warm. Sweet potatoes need warm temperatures to thrive. If your climate is on the cooler side, mulch your beds with black plastic to retain warmth. Installing row covers is another way to help keep your sweet potato plants warm.
• Weed the garden. Periodically pull weeds from the bed to avoid weeds competing for nutrients. As you weed, avoid using tools that will disturb or injure the sweet potatoes growing beneath the soil.
• Control disease and rot. Sweet potatoes can fall prey to diseases like white blister, scurf, or stem rot. To prevent these diseases, nourish your plants with compost tea and make sure the soil is moist—not overly dry or wet.

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