When and How to Plant Potatoes: Complete Growing Guide

Plant potatoes 2-4 weeks before your last expected spring frost when soil temperature reaches 45-50°F (7-10°C). Use certified seed potatoes, plant 3-4 inches deep in loose, well-drained soil with eyes facing up, spacing 12-15 inches apart in rows 24-36 inches apart. Hill soil around stems as plants grow to maximize tuber production.

Knowing exactly when and how to plant potatoes makes the difference between a disappointing harvest and a bountiful crop that feeds your family for months. Whether you're working with a backyard garden or larger plot, proper potato planting follows science-backed agricultural principles that have been refined over centuries since their domestication in the Andes.

Optimal Timing for Potato Planting

Timing is the most critical factor in successful potato cultivation. Planting too early in cold, wet soil leads to rot, while planting too late reduces yields as summer heat stresses the plants. The United States Department of Agriculture (USDA) recommends planting potatoes 2-4 weeks before your area's last expected spring frost date when soil temperatures consistently reach 45-50°F (7-10°C).

Potato Planting Timeline

• 6-8 weeks before planting: Begin chitting (sprouting) seed potatoes in a cool, bright location
• 2-4 weeks before last frost: Plant maincrop varieties when soil reaches 45-50°F
• After planting: Hill soil around plants when they reach 6-8 inches tall
• Flowering stage: Maintain consistent moisture for tuber development
• 80-120 days after planting: Harvest time depending on variety

Regional Planting Considerations

Successful potato planting requires adapting to your specific climate zone. The Cornell University Cooperative Extension emphasizes that planting schedules vary dramatically across regions:

Region	Planting Window	Soil Temperature Target	Special Considerations
Northern States	April-May	45-50°F (7-10°C)	Plant early varieties for short growing seasons
Southern States	February-March	50-55°F (10-13°C)	Avoid summer heat; plant for fall harvest
Coastal Areas	March-April	48-52°F (9-11°C)	Watch for late frosts in microclimates
Moderate Climates	March-April	50°F (10°C)	Can plant second crop in July for fall harvest

These regional variations reflect the potato's sensitivity to temperature extremes. In warmer southern regions, many gardeners plant potatoes in late winter for an early spring harvest before summer heat arrives, while northern gardeners must wait until soil warms sufficiently in spring.

Soil Preparation Essentials

Proper soil preparation creates the foundation for healthy potato growth. Potatoes thrive in loose, well-drained soil with a slightly acidic pH between 5.0 and 6.0. The University of California Agriculture and Natural Resources recommends:

• Test your soil pH 4-6 weeks before planting
• Incorporate 3-4 inches of organic matter (compost or well-rotted manure)
• Avoid fresh manure which can cause scab disease
• Create raised beds or mounds for better drainage in heavy soils
• Ensure soil is workable (not too wet) before planting

Working soil when it's too wet creates compaction that restricts root growth and tuber development. A simple test: squeeze a handful of soil—if water drips out, wait to work the soil.

Seed Potato Selection and Preparation

Never plant grocery store potatoes, which are often treated with sprout inhibitors and may carry diseases. Instead, use certified disease-free seed potatoes from reputable garden suppliers. The Maine Organic Farmers and Gardeners Association emphasizes that certified seed potatoes guarantee varietal purity and freedom from common potato diseases.

Before planting, consider chitting (pre-sprouting) your seed potatoes:

• Place seed potatoes in a single layer in egg cartons or trays
• Position in a cool (60-70°F), bright location for 2-4 weeks
• Look for short, sturdy sprouts (1/2 to 1 inch long)
• Discard any with long, weak sprouts or signs of rot

Step-by-Step Planting Process

Follow these research-backed steps for optimal potato planting:

1. Create planting trenches: Dig 3-4 inch deep furrows spaced 24-36 inches apart
2. Position seed potatoes: Place cut pieces 12-15 inches apart with eyes facing up
3. Cover with soil: Fill trenches with 2-3 inches of soil, leaving some coverage
4. Initial watering: Water gently but thoroughly after planting
5. First hilling: When plants reach 6-8 inches tall, mound soil around base
6. Subsequent hilling: Repeat every 2-3 weeks until plants flower

Hilling (mounding soil around growing stems) is crucial—it prevents greening of tubers from sun exposure and encourages additional tuber formation along buried stems. The Michigan State University Extension reports that proper hilling can increase yields by 20-30% compared to non-hilled plantings.

Post-Planting Care Requirements

After planting, consistent care determines your harvest success:

• Watering: Provide 1-2 inches of water weekly, keeping soil consistently moist but not soggy
• Weed control: Hand-pull weeds carefully to avoid disturbing shallow roots
• Pest monitoring: Check regularly for Colorado potato beetles and aphids
• Disease prevention: Avoid overhead watering to reduce fungal disease risk
• Fertilization: Apply balanced fertilizer when plants reach 6 inches tall

As plants approach flowering, reduce watering slightly to encourage tuber maturation. The final 2-3 weeks before harvest should have reduced moisture to allow skins to harden for better storage.

Harvest Timing Indicators

Knowing when to harvest determines potato quality and storage potential:

• New potatoes: Harvest 2-3 weeks after plants flower for tender, small potatoes
• Main crop: Wait until foliage yellows and dies back completely (typically 90-120 days)
• Test harvest: Gently dig one plant to check skin set before full harvest
• Weather timing: Harvest before first hard frost for best storage quality

Allow main crop potatoes to cure in a cool, dark, humid location for 10-14 days before long-term storage. Properly cured potatoes develop thicker skins that dramatically improve storage life.

Avoiding Common Planting Mistakes

Even experienced gardeners make these preventable errors:

• Planting too deep: Exceeding 4 inches depth delays emergence and reduces yields
• Skipping hilling: Results in fewer tubers and potential greening from sun exposure
• Overcrowding: Spacing less than 12 inches apart reduces tuber size and increases disease risk
• Using poor quality seed: Grocery store potatoes often carry diseases and sprout inhibitors
• Irregular watering: Causes cracking and hollow heart in developing tubers

By understanding these common pitfalls and following research-based planting practices, you'll maximize your potato harvest potential while minimizing common problems.

Can I plant regular store-bought potatoes?

No, grocery store potatoes are often treated with sprout inhibitors and may carry diseases. Always use certified disease-free seed potatoes specifically grown for planting to ensure healthy crops and prevent introducing pathogens to your garden.

How deep should I plant potatoes?

Plant seed potatoes 3-4 inches deep initially. As plants grow, hill soil around the stems, eventually covering them with 6-8 inches of soil. The initial planting depth ensures proper sprouting while subsequent hilling encourages additional tuber formation along buried stems.

How far apart should I space potato plants?

Space seed potatoes 12-15 inches apart within rows, with rows spaced 24-36 inches apart. Proper spacing ensures adequate room for tuber development, improves air circulation to prevent disease, and allows sufficient access for hilling and harvesting.

When is the best time to harvest potatoes?

Harvest new potatoes 2-3 weeks after flowering for tender small potatoes. For main crop storage potatoes, wait until foliage yellows and dies back completely (typically 90-120 days after planting). Harvest before first hard frost for best storage quality.

Why do I need to hill my potato plants?

Hilling prevents tubers from greening due to sun exposure, encourages additional tuber formation along buried stems, improves drainage, and suppresses weeds. Proper hilling can increase yields by 20-30% compared to non-hilled plantings, according to agricultural research.