Sweet potatoes are easy to plant, require a minimum of effort while growing and yield a bountiful harvest that will store well into the winter.
Sweet potatoes are easy to grow in places with more than a 120-day growing season. They are usually grown in sandy soil, which makes them easier to dig, but they thrive in most soils, even heavy clays.
Sprouting Slips
To start potatoes, purchase your favorites at the grocery store in mid-winter. Buying organic sweet potatoes improves the chances they will sprout. Let them sit in the pantry and when they begin to sprout, immerse the opposite end in a jar of water. The sprouts, called slips, are what will be planted.
Planting Slips
At least 2 weeks after the date of the last average frost, clip the slips from the potatoes with a scissors or knife. Remember which end of the slip was attached to the potato: that end will go in the ground and become roots and more potatoes. Longer slips should be cut in 4” to 6” pieces.
Till or hand-dig the potato bed to a depth of 8” to 10”. Sweet potatoes do well in low fertility soil but the addition of compost will loosen the soil and make the roots easier to dig in the fall. A string from one end of the bed to the other will help to keep the row straight. Using a tape measure or a stick cut to length, poke the slips into the soil 12” apart. Water well after planting and keep watered until signs of growth are observed. The slips have leaves but no roots so don’t be alarmed if they lose a few, or all, of their leaves. They will survive.
An alternative method is to use small bedding plant flats known as “six-packs” or small flower flats. Fill the pot or flat with potting soil and plant the slips, one to a cell or pot. Allow 2 weeks for roots to grow, then plant in prepared beds. This method requires more materials and work, but is much less of a shock to the slip.
Weeding and Watering
Sweet potato slips grow slowly at first but much more quickly by mid-summer, forming a tangled mass of vines 2’ deep and 8’ wide. Plants either side of the sweet potato bed may be engulfed so allow plenty of room.
Sweet potatoes have almost no pest problems, but they do require weeding until the canopy forms. After that, few weeds can survive. If rainfall is insufficient, make sure potatoes get 1” of water per week.
The tubers will be ready to dig from 100 to120 days after planting. The longer they are in the ground, the higher the vitamin content and the larger the potatoes.
Digging Sweet Potatoes
Dig when leaves yellow but don’t wait until plants are killed by frost as those tubers may not last in storage. Most of the potatoes are in a tight cone-shaped cluster directly below the main stem. However, some will be growing a foot or even 18” out from the stem, and there is no way to know where they are. Digging carefully, start about 18” from the stem. Some sweet potatoes will get nicked but they will heal.
Curing Sweet Potatoes
Potatoes grown in sandy soil probably need not be washed. Those grown in clay soil may need rinsing to remove stuck-on soil. Be sure to let the potatoes dry well for several hours outside, then move to a protected spot to “cure” for 7 to10 days. This curing of the sweet potatoes allows the skin to toughen and ensures long storage. Ideal storage conditions for sweet potatoes are 50° to 60° and 60% to 70% humidity. With proper curing and storage the potatoes should last for several months.
Sweet potatoes are great baked, or try them combined with apples and onions in this easy saute.
