Sweet potatoes (Ipomoea batatas) are warm weather crops that require a long growing season to produce large tubers. Native to Central and South America, heirloom varieties of sweet potatoes are generally not available in the supermarket. If you enjoy the taste of the old-time sweet potato, you will need to grow them in your garden. Some heirloom varieties to consider include Betty's, Edna Evans, and Golden Slipper. Old-time sweet potatoes grow on vines and are started with slips, which are small sweet potato vines sold in nursery pots. Plant your old time sweet potato slips after the last frost, when the soil warms.
Remove all weeds from the planting area either by hand or by using a hoe.
Test the pH of the soil in the planting area. A soil sample, delivered to your county cooperative extension office, can yield invaluable information on the current state of your soil. The analysis will also offer suggestions on appropriate soil amendments. Sweet potato slips require a soil pH of 5.0 to 6.5.
Loosen the soil in the planting area by digging into it with a shovel or garden fork. Add the soil amendments recommended by the soil analysis, and mix them into the soil.
Create a ridge, 8 inches in height and width, from soil. The length of the ridge will depend upon the space in your garden. If you need to plant more than one row of sweet potato slips, place the ridges 4 feet apart.
Dig planting holes in the ridge, 12 to 18 inches apart. The holes should be the same depth and twice the width of the pot in which the slips are growing.
Place the roots of the old time sweet potato slips into the holes, and pack soil around the plants.
Water the plants to a depth of 5 inches and supply them with 1 inch of water a week.