Trott column: How to grow your own potatoes
Mashed, scalloped or fried, potatoes are a staple in our American diet.
Mashed, scalloped or fried, potatoes are a staple in our American diet. Nothing is more satisfying than eating potatoes out of your own garden. If you haven’t thought about potatoes yet, now is a great time to select varieties and think about planting once the weather cooperates.
Potatoes are grown from seed tubers, not true seed. Purchase disease free tubers from your local nursery, favorite catalogue, or local grocery store (make sure to purchase “seed potatoes”.) Don’t use potatoes you have purchased (to eat) from the grocery store. These are often sprayed with chemicals to prevent sprouting.
Choosing potato varieties
Use mealy or dry-fleshed potatoes, like russets, for baking, frying and mashing. As mashed potatoes, they will not be gluey, and they will absorb gravy, butter or sour cream. They may fall apart in a soup, or when boiled for a potato salad.
Waxy or moist-fleshed, round potatoes hold together when cooked. Potato chunks in soups, curries, frittatas, and salads are usually waxy varieties. You can pan-fry leftover boiled potatoes without them falling apart. When you mash waxy potatoes, they can become sticky.
Many potato varieties fall somewhere in between truly waxy and completely mealy. All-purpose potatoes such as Yukon Gold usually have a balance of waxy and mealy starches.
Potatoes grow best in well-drained soil with pH 6 to 6.5. Have your soil tested to determine your soil’s pH and whether it should be amended. Water to a depth of 1 inch (shallow watering is of no value when growing potatoes). Mulch around your plants at a depth of 3-4 inches to keep the soil cool and moist and prevent weeds. Frequent, shallow cultivation to control weeds is recommended for optimal plant growth and yield.
Plant seed pieces in early spring as soon as the soil warms. Cut seed pieces at least one day prior to planting to allow the cut surfaces to dry. (Drying allows the pieces to form a wound, which creates a disease protective surface.) Make sure pieces have at least two eyes, and are no smaller than about 2 ounces. Larger seed pieces will generally emerge faster than smaller ones. Small potatoes may be planted whole. Plant seed pieces cut side down, 10-12 inches apart and about 3-5 inches deep, in rows 30-36 inches apart. Space pieces closer for smaller tubers and farther apart for fewer but larger tubers. Cover pieces with 4 inches of soil or compost.
Greensprouting was originally developed for use with small, whole-seed tubers. Also called “chitting” or "pre-sprouting,” greensprouting involves exposing seed tubers to natural or artificial light in a warm environment before planting. This allows the development of short, strong, green sprouts and, if all goes well, a faster-growing plant. Researchers have shown that greensprouting can hasten plant development and tuber growth – a significant benefit when growing long-season cultivars in short-season climates such as ours.
Start hilling plants when the main stems are about a foot tall, and once or twice more during the growing season. (At the end of the season, you will have hilled 6-8 inches of soil in total along the plants.) Potatoes will grow on thin side shoots that emerge from the main stem (stolons), and these stolons should be kept covered with soil to avoid exposing the young potatoes to sunlight. Sunlight can turn potatoes green and cause the formation of potentially toxic and bitter-tasting chemicals in the skin and flesh.
- During the enlargement of the tubers, moisture stress can cause knobby or hollow potatoes and can prevent the plant from producing new tubers.
- Light soil is the best for growing large, smooth potatoes, but not if it gets too dry for good tuber growth.
- Soak the soil thoroughly when watering, once or twice a week.
- One inch of rainfall per week is good.
- An inch of water will wet a sandy soil to a depth of ten inches, a heavy clay soil to six inches. If your soil is sandy, water more often than once a week.
- Use a trowel to see how far down the soil is wet. If it is only an inch or two, keep the water running.
- Frequent, shallow cultivation with a hoe or other tool will kill weeds before they become a problem.
- Do not cultivate too deeply. Hoe just deeply enough to cut the weeds off below the surface of the soil.
- Be careful not to damage the potato plants when cultivating, and continue hilling soil up around the plants.
For more information about growing vegetables in your garden, visit: www.extension.umn.edu.
See you in the garden!
“What I say is that, if a man really likes potatoes, he must be a pretty decent sort of fellow.” ~ A.A. Milne
Robin Trott is a horticulture educator with University of Minnesota Extension. Contact her at 320-762-3890, or at