How to Plant Potatoes

Potato plants (Solanum tuberosum) produce starchy, edible tubers. The plants grow above ground, but the tubers grow under the soil and must be dug up at harvest time. As annual plants, potatoes need a long growing season that is not too hot. Even in many warm climates, though, planting early in spring can result in a bountiful potato tuber crop when the plants receive proper care. Get seed potatoes into the ground no sooner than two weeks before the average annual date of your location's last freeze of 28 degrees Fahrenheit or colder because a freeze will kill sprouts that have emerged.

Plant the seed potatoes only when the soil has reached a temperature of 40 degrees Fahrenheit, otherwise, the soil is too cold and the plants will not germinate well.

Certified, disease-free seed potatoes -- whole potato tubers available from plant nurseries, garden centers, and online and mail-order suppliers -- are produced specifically for planting. They are free of diseases that can infect the potato crop and reduce yield. Never use potato tubers from a grocery store because they usually have been treated to retard sprouting and aren’t suitable for planting. They also may carry diseases, even if they appear perfectly healthy.

Do not plant potatoes in areas where other members of the Solanaceae family have grown during the past two years.

Seed potatoes

Clean, sharp knife

Scale measuring ounces

Cut each seed potato into small pieces using a sterilized knife. Wipe the blade off with alcohol and allow to dry before using. Each piece should be approximately 1 to 2 inches across in size. Seed potatoes the size of an egg can be planted whole. An eye is a little, dark bud or dimpled area on the outside of the potato. A sprout grows from each eye and becomes a potato plant.

Allow the cut seed potato pieces to air-dry for at least several days to several weeks. During that time, a protective film will cover their cut areas. If the seed potatoes are not allowed to cure, they can rot when planted in the ground.

Potato plants do best in well-drained, fertile soil. Most gardens benefit from the addition of compost or well-rotted manure to their soil prior to planting. Spread a layer of compost or well-rotted manure about 1 inch thick on top of your garden's soil, and mix it well with the upper 6 to 8 inches of the soil. If you prefer, instead sprinkle 1 1/2 pounds of dry 5-10-10 fertilizer across each 100 square feet of soil surface, and use a shovel or tiller to mix the fertilizer into the upper 3 to 5 inches of soil.

Do not apply too much nitrogen in the soil at the time of planting or the plants will produce lush top growth at the sake of producing tubers.

Potatoes prefer a soil pH of 4.8 to 5.5.

It's always a good idea to get your soil tested before planting so you know what amendments are required for proper growth.

Plant your seed potato pieces 4 inches deep in holes wide enough to hold the pieces. Place the cut sides down so that the eyes point upward. The pieces should be spaced 10 to 12 inches apart, with 3 feet between rows of seed potatoes. The closer the plants are, the smaller the potato tubers will be; widely spaced plants produce larger tubers. Fill the planting holes with soil to cover the seed potato pieces, making the soil level even with the surrounding ground.

Soak the soil with water immediately after the seed potatoes are planted. Use enough water to wet the soil to a depth of about 1 inch. Repeat the soaking every week; if the soil is very sandy, however, it won’t hold the water well and will require more frequent soakings.

The potato plants will begin to emerge from the soil about two to three weeks after the seed potatoes were planted. After the plants appear, add a 3- to 4-inch layer of mulch to the top of the soil surface to help conserve soil moisture. Don't let the mulch touch the plants, though, because it can cause the stems to rot as well as contribute to diseases.

As the potato plants reach 6 to 8 inches in height, add 2 to 3 inches of soil onto the top of the soil around the plants. This process, called hilling, keeps the new tubers from being exposed to sunlight and getting sunburned, which ruins them.