Plant Search

Search for any plant to learn how to grow it.

Potato Kennebec

Potato Kennebec

Solanum tuberosum 'Kennebec'

vegetable

Kennebec is a mid-season potato variety prized for its excellent all-purpose culinary qualities, smooth tan skin, and creamy white flesh. Originally developed in Maine in 1941, it produces high yields of medium-to-large tubers with shallow eyes and outstanding flavor. This versatile potato is ideal for baking, frying, mashing, and boiling, making it a favorite among home and commercial growers.

Growing Conditions

☀️
Sun: Full sun, 6-8 hours daily minimum; 8+ hours optimal for maximum yield
💧
Water: Consistent moisture is critical—1-2 inches per week through rain or irrigation. Keep soil evenly moist but not waterlogged. Water deeply at base to avoid wetting foliage. Reduce watering slightly after flowering to allow skin set. Drought stress reduces tuber size and quality.
📏
Spacing: 12 inches
📅
Days to maturity: 70-90 days to harvest-ready size (mid-season variety); 65-75 days for small new potatoes
🌱
Planting depth: Plant seed potatoes 4 inches deep; later hill up soil around emerging shoots to 8-10 inches for increased yield and to prevent greening

Soil

Type: Well-draining, loose, slightly acidic loamy or sandy soil, free from rocks and debris
pH: 5.8-6.5
Amendments:
Compost or well-rotted manure (2-3 inches worked in) Perlite or sand for drainage improvement Wood ash (in moderation for pH adjustment) Avoid fresh manure, which promotes scab

Growing Zones

Find your zone →

Thrives in zones 3-8, with best production in cooler climates of zones 3-6

3a 3b 4a 4b 5a 5b 6a 6b 7a 7b 8a

Sign up to see your zone highlighted.

Growth Stages

1

Seed Piece Sprouting

10-14 days until emergence visible, 2-3 weeks until shoots above soil

Cut seed potatoes (2 ounces each with 2+ eyes) are planted in prepared soil. Shoots emerge from soil surface within 2-3 weeks.

Plant in early spring when soil is workable (50°F+). Allow cut pieces to heal 1-2 days before planting. Ensure consistent soil moisture from planting through emergence.

2

Vegetative Growth & Hilling

4-6 weeks

Plants develop leafy shoots and begin forming underground stolons (tuber precursors). Visible vines reach 6-12 inches tall.

Begin hilling when shoots are 6-8 inches tall; repeat every 2-3 weeks as vines grow, covering stems with 4-6 inches of soil. This promotes tuber formation, prevents greening, and increases yield. Maintain consistent water and apply balanced fertilizer (10-10-10) after first hilling.

3

Flowering & Tuber Bulking

3-4 weeks peak flowering; tuber bulking continues throughout

Plants develop clusters of white, pink, or purple flowers. Underground, tubers rapidly expand. Vines reach full size (18-24+ inches).

Flowers typically appear 8-10 weeks after planting. Stop hilling once vines flower. Maintain steady water supply; tubers gain most mass during this stage. Monitor for early/late blight and pests. Flowers can be removed to redirect energy to tubers (optional).

4

Skin Set & Maturation

2-3 weeks

Flowers fade and wilt; vines remain green. Tuber skin hardens and develops thickness. Foliage may yellow as plant matures.

Begin reducing watering slightly to allow skin thickening (important for storage). Do not harvest too early or skin will rub off easily. Kennebec is ready 70-90 days from planting; wait until foliage yellows/dies back for best results.

5

Harvest

Single harvest event at end of season

Foliage dies back completely; tubers reach market size (1.5-3+ inches) with hardened skin.

Cut back dead vines 2 weeks before harvest if desired. Dig carefully to avoid bruising. Harvest when soil is dry for easier digging and to minimize disease. Cure harvested potatoes in a cool, dark, humid place (50-60°F, high humidity) for 10-14 days before storage.

Common Pests

  • Hand-pick adults and orange egg clusters. Apply neem oil, spinosad, or pyrethrin sprays. Use row covers on young plants. Rotate crops yearly. Bacillus thuringiensis (Bt) products may help with larvae.

  • Use reflective row covers early season. Spray insecticidal soap or neem oil. Maintain plant health; avoid excess nitrogen which attracts them. Yellow sticky traps for monitoring.

  • Spray with strong water stream to dislodge. Apply insecticidal soap, neem oil, or horticultural oil. Release ladybugs or parasitic wasps. Avoid over-fertilizing with nitrogen.

  • Crop rotation (avoid potatoes in infested soil for 3+ years). Till soil to expose larvae to predators. Trap potatoes buried in soil to monitor. Plant resistant varieties when possible. Add beneficial nematodes to soil.

  • Remove lower infected leaves. Mulch to prevent soil splash. Spray with copper fungicide or chlorothalonil. Improve air circulation. Water at base only. Rotate crops. Avoid overhead watering.

  • Remove infected plant material immediately. Apply copper or mancozeb fungicide preventatively in humid conditions. Ensure good drainage and air flow. Avoid overhead watering. Plant in well-spaced rows. Remove volunteer potatoes.

  • Plant seed pieces that are disease-free. Maintain slightly acidic soil pH (5.8-6.2). Avoid fresh manure. Ensure consistent moisture. Do not use lime. Rotate crops.

Uses

🍳

All-Purpose Cooking

Culinary

Kennebec potatoes are the quintessential all-purpose potato, excelling in baking, boiling, frying, mashing, and potato salads. Their waxy-to-medium starch content and creamy texture make them ideal for nearly every potato dish. Professional chefs and home cooks favor Kennebec for French fries and roasting. [source]

🍳

French Fries & Chips

Culinary

Kennebec is the preferred potato for commercial and homemade French fries due to its low sugar content, excellent color, and ability to achieve crispy exteriors with fluffy interiors. It is the standard variety used by major fast-food chains. [source]

🏠

Long-Term Storage

Household

Kennebec potatoes store exceptionally well for 4-6 months when kept in cool, dark, humid conditions. The relatively thin skin and dense flesh resist sprouting and decay, making them ideal for winter storage in root cellars or cool basements. [source]

💊

Nutritional Value

Medicinal

Potatoes, including Kennebec, are rich in vitamin C, potassium, vitamin B6, and manganese. Potatoes are naturally gluten-free and contain resistant starch when cooled after cooking, which may support digestive health and improve insulin sensitivity. [source]

🦋

Livestock & Garden Wildlife Feed

Wildlife

Potato plants and tubers have historically been grown to provide supplemental nutrition for livestock (pigs, chickens) and poultry. Potato vines are also used as a cover crop and green manure to improve soil. [source]

This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.

Harvest Tips

Kennebec reaches full maturity 70-90 days after planting. For new potatoes, harvest 50-60 days after planting when vines flower and tubers are 1-1.5 inches. For storage potatoes, wait until vines die back naturally or cut back foliage 2 weeks before intended harvest. Dig carefully with a potato fork, working from the side to avoid spearing tubers. Harvest on a dry day and let potatoes air-dry for 1-2 hours before storing. Cure in a dark, humid place at 50-60°F for 10-14 days before storing at 45-50°F.

Fun Facts

  • 🌱 Kennebec was developed at the University of Maine in 1941 and is named after the Kennebec River in Maine, reflecting its origins in America's historic potato-growing region.
  • 🌱 Kennebec potatoes are so integral to American food culture that they are the official standard potato for McDonald's French fries in the United States, establishing it as one of the world's most recognized potato varieties.
  • 🌱 Potatoes are the world's fourth-largest food crop after rice, wheat, and corn, and Kennebec remains one of the most widely grown varieties globally for both commercial and home cultivation.

Want to save this plant and get personalized recommendations?

Sign up to add plants to your list, see your growing zone highlighted, and get planting timelines based on your frost dates.