Sweet potatoes provide one of the most nutritious crops you can grow in your vegetable garden. But red sweet potatoes need a long growing season, which makes growing them in northern gardens a challenge. However, if you prepare the soil several weeks in advance and plant red sweet potato varieties bred for production in your climate, you can grow your own crop of delicious sweet potatoes no matter where you live.
Select a spot in full sun to plant your sweet potatoes. Do not plant sweet potatoes in soil where grass has grown in the previous two years.
Prepare the soil 2 to 3 weeks prior to planting sweet potatoes.
Till the top 6 inches of soil. Spread a 3- to 4-inch layer of compost on the soil and re-till the soil.
Test the pH of your soil. The ideal pH for sweet potatoes is 5.6 to 6.5. Add sulfur (according to package directions) to the soil if you need to lower the pH.
Create a mound of soil 6 to 9 inches tall and wide along the length of the row. Space rows 3 to 4 feet apart.
Plant certified disease-free sweet potato slips 3 to 4 weeks after your last predicted frost date. Plant each slip 3 to 4 inches deep (slips are generally 8 to 10 inches tall) in the mounded rows. Gently firm the soil around the base of the slips. Space slips 12 to 18 inches apart.
Mix a commercial or organic 5-10-10 liquid fertilizer in 1 gallon of water. Follow package instructions for the amount of fertilizer to add to the water. Water each slip with the fertilizer/water mix.