Potatoes Offer Healthy Sustainability
By Anita B. Stone, North Carolina
It’s been said that each one of us consumes 126 pounds of potatoes each year, including the popular Russet and Idaho baking potatoes, yellow Yukon Gold, Norland Red, Russian Blue, Fingerling, and White Rose potatoes. Most of us enjoy eating potatoes, but only a small number of us grow our own. And yet, planting and harvesting potatoes is one of the simplest and highest-yielding crops to grow.
You can start from seed, but it’s easier and quicker to plant tubers, called “seed potatoes.” Always start with clean, certified seed potatoes purchased from a reputable source to reduce the risk of diseased plants.
Potatoes can be planted in early spring, usually during the month of March here in North Carolina. They like cool weather. In northern climates, potato crops can be planted when dandelions bloom in the fields, while others plant on St. Patrick’s Day. If an unexpected freeze occurs, cover any seedlings or young plants with old blankets, towels or sheets.
The recommended way to plant potatoes is to find a well-drained, fertile site. If the soil is rocky or compact, place the seed potatoes on the ground and cover them with mulch instead of soil, using hay or straw, leaves or grass clippings. I used an organic method of weed control by placing the seed pieces on the soil surface and covering them with about six inches of straw. The sprouts emerged through the straw and weed growth was inhibited. This worked well and kept the tubers cool, the soil moist and were easy to harvest.
Because my site is about one acre, I surrounded it with chicken wire fencing. I used the old-fashioned trenching method and then hilled them, just as you would with mulch. Hilling also discourages weeds and gradually creates sufficient space for the tubers to develop.
Dig a trench about eight inches deep and six inches wide at the top, tapering at the bottom to about three inches wide. Place the seed potatoes cut-side down (eye up) about 12 inches apart in the trench. Cover the area with three to four inches of soil. Straw can be used to top it off. Watch for green leaves to pop out from the soil in about two weeks.
Foliage will grow from the eye of the potato. If the potatoes have already sprouted, just leave the sprouts in place when you plant. If you can’t plant the potatoes immediately, place them in the refrigerator or in a cool, dark place where they will not dry out.
When the stem begins to show above ground and grows about eight inches tall, hill up again using a hoe to gently fill the trench with more soil. Leave about four inches of the plant showing. Repeat the procedure about three weeks later, then again after several weeks have passed. It is best to hill up in the morning when plants stand tall.
Plant potatoes in the same spot for a maximum of four years, then rotate the area with something other than the potato (nightshade) family, including tomatoes, eggplant, and peppers (green, yellow, red and hot).
Instead, plant beans, peas, corn or cabbage. Or use a rye cover crop for one year.
If you prefer early yields, seed potatoes can be pre-sprouted in a process called “chitting out,” or “greening.” To do this, just lay them in a shallow tray not touching and put them into a warm place with a temperature of about 70°F with medium light. The potatoes may turn green but this is okay for seed potatoes. Once they begin to sprout, simply plant them being careful not to break the sprouts.
Diseases can be devastating. Recognizing diseases can improve the crop and save the potatoes before they fall prey to a slow decline.
Scab occurs from perpetual cropping; therefore, crop rotation is a must and is the first rule in disease control. But awareness will often save the crops. Potatoes need moisture to develop good tubers. They are shallow-rooted and become sensitive to a lack of moisture. Because potato pests are extremely common, watch for clues that nature is invading the crops. Slugs enjoy damp mulch.
If your soil is extremely alkaline it will encourage scab fungus, which causes barklike growth on the skin of potatoes, resembling warts. Scab can be pared away for eating but it stays in the soil for years and will affect each crop.
Treat the soil by adding more acidic components. A pH should read between 4.5 and 5.5. Add sulfur at a rate of about one-half pound over the top of a 15- to 20-foot trench and plant scab resistant varieties, including resistant cultivars like Norland, Goldrush, Katahdin, Kennebec, Russet, Superior and Red Pontiac. Or, gently toss newly cut pieces of seed potatoes with sulfur in a plastic bag before planting, in much the same way you would bread chicken for frying.
The Colorado potato beetle displays a black and yellow stripe figure and is extremely destructive. Handpick the bugs and dunk them into a container of soapy water and mash them with the back of an old spoon. Then check for small yellow eggs in clusters underneath the leaves. If you find any, spray the leaves with insecticidal soap, which can also be used to combat the beetle as well as aphids.
Blight caused the devastating Irish Potato Famine in the 1800s and still threatens potatoes today. Late blight appears as brown or black lesions on foliage or stems. Wet leaves and high humidity favor the disease, but infected seed potatoes and plant debris spread late blight. Plant disease resistant varieties and space enough area between rows for air movement. Keep away from sunflowers since they inhibit the growth of potatoes. It’s been said that if you spot lamb’s quarters growing in your patch, you will have a poor crop.
Use a clean, sharp knife to cut large tubers into pieces from one to four ounces, each, making sure there is an eye or more on each piece. Keep plenty of flesh around the eyes because this is the food that the plant will require during the beginning weeks of growth.
Early potatoes mature in about 55 days. Late potatoes develop in 90 days or more. About two or three weeks after the potato plants flower, which is a sign of healthy tubers, check for a crop of new spuds. Carefully poke into the potato hill with your hand to see what you can find. Check out potatoes from several plants carefully without damaging the roots.
For mature potatoes, wait until the foliage wilts and dies back before harvesting. Choose a day when the soil is dry and work in the morning hours when it isn’t hot. Use a digging fork or trowel and gently dig or lift the potatoes out of the hill, careful not to stab their skins. If the soil is wet, let the potatoes air dry on the surface before gathering them, but don’t expose them to too much sunlight.
If you want to keep some of your crop for winter use, “cure” them by toughening up the skin before storing them. Leave the potatoes in the ground for another two weeks or store recently dug potatoes in a dark and humid place at 60–65°F for two weeks. Don’t wash the potatoes because the skins will get damaged.
After curing, keep the potatoes in a dark, dry, cool area. If stored colder than 30–40°F the potatoes will rot; above 50 degrees F the potatoes will begin to sprout. Burlap bags, slotted crates or baskets are ideal containers and often a cellar, shed or a garage is a good storage spot. Also, be sure not to store potatoes with apples because the ethylene gas that apples give off will promote potato sprouting. If you’re faced with potatoes that begin to sprout while in storage, you can place dried lavender or sage in with the potatoes.
Alternative potato cropping is performed by farmers and urban dwellers. Some people grow potatoes in a sandy loam inside a free-draining barrel. The trick is to add more soil as the vine grows and when fall frosts arrive, begin the harvest. Never bury the vine completely. Also, make sure the barrel is placed in direct sunlight for maximum growth.
Originally published in the May/June 2012 issue of Countryside & Small Stock Journal.