Potatoes originated in the Andes and were domesticated as long as 10,000 years ago. Currently, they come in fourth place in worldwide food production. This vital spud is a herbaceous perennial plant which can grow year-round in moderate climates but will not survive hard frosts. Cold weather late in the season can damage entire crops of potatoes, making them more likely to bruise and rot during harvest and storage. Potato plants sprout a canopy of lush green leaves and white or purple flowers, but take note that seeds will not grow the same variety as their parent. Don’t fear! You can cut up last year’s potatoes and plant them to produce another crop.
The Kennebec potato is a mid- to late-season variety that produces large oval tubers with white flesh and thin tan skin. The earthy flavor and moist but starchy texture make them an excellent choice for baking and frying, though it’s generally considered an all-purpose type. Kennebecs are resistant to many strains of potato viruses and foliage late blight. They’re also great for longer term storage. Space plants fairly close together to prevent tubers from getting too large, and expect large plants with big leaves and high yields. Plants are susceptible to sunburn, so provide some afternoon shade if you live in an especially sunny area.
Seed: Most potato varieties are not grown from their seeds. Instead, plant pieces of previous year’s potatoes or whole small potatoes grown specifically for this purpose, which are known as “seed potatoes.”
Vegetative: Can be grown from pieces of potatoes with at at least one or two “eyes.” Small potatoes can be planted whole in the soil.
Planting Depth: 3–4″
Space Between Plants: 8–10″
Space Between Rows: 18–24″
Sprouting Soil Temperature: 45–50°F
Days for Sprouting: 10–14
Sow Indoors: Not recommended.
Sow Outdoors: From average last frost date to 2 weeks after average last frost. You can also overwinter in USDA Zones 8 and up by starting plants in the fall.
Prefers moderate temperatures. Will not grow well when temperatures are consistently above 80˚F, so be sure to plant when the risk of frost has passed while allowing enough time for potatoes to develop before extreme summer heat sets in or fall frosts begin to settle. If you live in USDA Zone 8 and higher, plant in fall for a spring harvest.
Natural: Full sun. Provide partial afternoon shade in extremely sunny areas.
Artificial: Will sprout well under standard fluorescent bulbs.
Soil: Grows well in well-drained loamy or sandy soil. If your soil has a high clay content, you will need to prepare soil before planting. A pH of 4.8 to 6.0 will keep plants healthy and nourished. Potatoes prefer more acidic soil and are more likely to develop diseases if soil is not acidic enough. Measuring pH levels prior to planting is important if you are unsure of your soil quality.
Soilless: An alternative outdoor growing method to traditional planting is called “mulch planting.” Loosen the soil and place potatoes on the ground. Cover with a layer of hay/straw, pine needles, sawdust, etc. to protect them from the sun and cooler weather. Once the plants start to emerge from your mulch, add another layer between 4 and 6″ thick.
Hydroponics: Will thrive in a hydroponic system using perlite or pebbles as growing media.
Aeroponics: Will thrive in an aeroponic system.
Water: Requires moderate levels of water. Soil should be kept evenly moist until after the plant has stopped flowering. After flowering, begin to reduce water by about half (depending on how hot the temperature is) as this will encourage the plant to start sending energy out of the leaves and into the tubers.
Nutrients: Soil should be prepared approximately 4 to 6 weeks before planting by adding compost or a fertilizer that is heavier on potassium and phosphorous (e.g., 1-2-2 or 5-10-10). If working with a soil that is clay-heavy, make sure to add organic material a few weeks in advance of planting to loosen the soil. Avoid fertilizers that will make soil less acidic, such as ones that contain high levels of lime.
Foliar: Use a fish or seaweed emulsion throughout the growth stages, but be careful of over-fertilizing since too much nitrogen will cause the plants leaves to grow, leaching energy from the tubers themselves. We recommend spraying in the early mornings.
Mulching: As plants grow, continue to add mulch or compost around the base of the plant to protect the tubers from cooler weather and/or sunburn. If using a mulch planting technique, add 4 to 6″ of mulch once the foliage starts to grow.
Disease(s): This variety is resistant to potato viruses S and X and foliage late blight, but watch out for:
Rotation: Although not required, an annual crop rotation will help keep your soil healthy and potatoes nourished. Potatoes may be rotated with most other crops but do best when alternated with alfalfa, grains, or grasses.
Companions: Grows well with peas, corn, eggplant, lettuce, onions, members of the Brassica family, and parsnips. Avoid cucumbers, kohlrabi, tomatoes, and members of the melon family.
Harvest: Should be harvested approximately 100 to 140 days after planting or when foliage and vines have died. Potatoes can be harvested by loosening the surrounding dirt with a shovel or spade, being careful not to dig too close to the plant as you can cut the tubers.
Storage: To store, allow potatoes to “cure” in temperatures of about 50 to 60°F in a humid location. After they have cured, keep tubers in a cool environment of about 40°F for several months. Potatoes may be kept in the refrigerator if desired, but be aware that this will cause the starch to turn to sugar, changing the flavor of the potato. Keep potatoes away from onions or apples as these can cause the potato to rot.
History: The Kennebec potato was bred by the USDA in Presque Isle Station, Maine in 1941.
Preserve: Can be frozen by cutting potatoes into smaller pieces, blanching, and freezing.
Prepare: The potato is one of the most popular food items in the world and can be found in a wide variety of recipes. One of the most common ways to prepare potatoes is by frying them. This can be done by washing and peeling your potatoes before tossing them into a hot pan of oil. Potatoes may also be baked, sautéed, steamed, or even grilled. If you have a preferred way to cook, chances are you can find a way to incorporate potatoes! Kennebec potatoes are best suited for frying.
Nutritional: A good source of vitamin(s) B and C, potassium, fiber, antioxidants, and manganese.
Medicinal: They have been found to possess certain compounds (kukoamines) that may help lower blood pressure.
Warnings: While potatoes have many health benefits when eaten in their unprocessed form, they often come fried or loaded with high calorie toppings (hello, bacon and cheese!). Green potatoes should also never be eaten as they contain solanine, which is a poison commonly found in the nightshade family. Eating green potatoes can cause severe gastrointestinal pain and in very serious cases, hallucinations, fever, and seizures.
If you’ve got some time on your hands and a hankering for the PERFECT French Fry, try this adventure of a recipe.