Potato Plant Growth Stages: 6 Key Phases For Maximum Yield

Potato Growth Stages: How Fast Do Potato Plants Grow?

Potatoes are a staple crop for gardeners and homesteaders, offering versatility in the kitchen and resilience in the garden. Although the bounty appears beneath the soil, understanding the lifecycle of the potato plant—from dormant tuber to lush greenery, from bloom to harvest—is key for growing robust, flavorful spuds. In this comprehensive guide, we break down each stage of potato growth, covering what happens above and below the soil, care requirements, and troubleshooting tips for every step in the process.

Overview: The Potato Life Cycle

• Sprouting and Emergence
• Vegetative Growth
• Initiation of Tubers
• Tuber Bulking
• Flowering and Maturation
• Senescence and Harvest

This cycle, from first sprout to mature harvest, generally spans 10-20 weeks, depending on the variety and environmental conditions. Below, we detail each stage, what to expect, and what your plants need most at every phase.

Sprouting and Emergence

Potato plants begin their journey from seed potatoes—either whole or cut pieces of certified seed tubers, each with at least one or two “eyes.” Once planted in the cool, well-drained soil of early spring, these eyes break their dormancy and begin to sprout.

• When to Plant: Plant potatoes 2-4 weeks before your area’s last expected frost. Soil temperature should be at least 45°F (7°C) for optimal sprout development.
• How to Plant: Place seed potato pieces 4-6 inches deep and 12 inches apart in rows spaced 2-3 feet apart for garden beds. For containers or grow bags, use one seed potato per 5-gallon bag, three per 10-gallon bag, and four per 15-gallon bag.
• Soil Preparation: Work in aged compost to improve fertility, and ensure the soil is loose to facilitate easy sprouting and tuber development.

What to Expect:

• Sprouting typically occurs within 2-4 weeks after planting, with shoots emerging above soil soon after.
• Roots begin establishing themselves, preparing the plant for vigorous vegetative growth.

Vegetative Growth

Once shoots emerge, potato plants rapidly develop leafy, grass-green foliage, typically reaching 1-1.5 feet tall and wide. The plant’s energy is concentrated on building a robust canopy of stems and leaves, which in turn powers underground development through photosynthesis.

• Importance of Light: Full sun is critical for strong vegetative growth and maximum tuber yield.
• Water Requirements: Maintain consistently moist soil but avoid waterlogging.
• Fertilization: Apply a balanced, low-nitrogen fertilizer early to support foliage and root development, but avoid over-fertilizing, which can delay tuber formation.

What to Watch For:

• Strong, healthy green growth signals the plant is preparing for tuber formation.
• Leggy or pale foliage may indicate insufficient sunlight or poor soil nutrition.

Initiation of Tubers

Approximately 15-30 days after the shoots emerge from the soil, potato plants enter the critical phase of tuber initiation.

• Cells in specialized underground stems (stolons) begin to swell, forming the initial tuber buds.
• This stage is invisible above ground but marks the moment when the plant redirects energy from leaf growth to forming edible tubers below.
• Consistent moisture and nutrients are especially key during this period.

Tuber Growth (Tuber Bulking)

From about 45 to 90 days after shoots have appeared, the initial buds expand as the plant diverts energy into tuber bulking.

• Tubers grow in both size and density but no new tubers are formed at this point; only the initiated ones will mature.
• This is when most of the final potato yield is determined.

Managing Tuber Growth:

• Hilling: Regularly mound soil, straw, or mulch up around the plant’s base to prevent tubers from being exposed to sunlight, which turns them green and bitter. Hilling also helps suppress weeds.
• Watering: Keep soil consistently moist. Erratic watering can result in cracked, irregular, or hollow tubers.
• Nutrition: A final boost of potassium-rich fertilizer at the start of this period can support tuber swelling.

Above-Ground Signs of Tuber Growth:

• Plants may appear to “stall” in height as energy is redirected underground.
• Leaves may begin to yellow slightly as the plant enters the next stage toward maturity.

Flowering and Maturation

The arrival of small, star-shaped potato flowers signals the peak of tuber growth and the start of plant maturation. Depending on variety and growing conditions, not all potatoes will flower, but if they do, it’s a helpful signpost in the growing calendar.

• Flowering: Flowers can appear as few as 7-8 weeks or as many as 12-16 weeks after planting, depending on the potato variety and environmental factors.
• What They Mean: Flowering indicates that the tubers are swelling rapidly and can be harvested soon as “new potatoes,” or left to mature further for storage crops.

Care and Maintenance:

• Continue hilling if tubers remain near the soil surface.
• Keep soil evenly moist, but reduce watering as leaves begin to yellow in late maturation.

Senescence: Maturation and Harvest

In the final stage, the potato plant enters natural senescence. Leaves and stems turn yellow and die back, and the plant stops directing energy into the foliage. Instead, it channels the rest into the tubers, finishing their development and hardening their skins for storage.

• When to Harvest:
• New Potatoes: Harvest 2-3 weeks after flowering, while skins are still thin and delicate.
• Storage Potatoes: Wait until most of the foliage has died back and the skins are thick and set (usually 16-20 weeks after planting).
• How to Harvest: Use a digging fork or your hands to gently unearth tubers, taking care not to damage them.

Post-Harvest Curing:

• Let tubers air-dry in a cool, dark place for 1-2 weeks to further toughen skins and improve storage life.

Potato Varieties and Time to Maturity

First and second early types are good for small spaces and containers, delivering speedy, tender harvests. Maincrop potatoes take longer but produce larger tubers with thicker skins that store well.

Growing Tips and Best Practices

• Use Certified Seed Potatoes: Reduce disease risk and improve yields by starting with disease-free seed tubers.
• Cut Large Seed Potatoes: If using large tubers, cut them into pieces with at least one or two eyes each. Allow the cut surfaces to dry for a day before planting to prevent rot.
• Soil Health: Amend with compost for fertility, and rotate your potato plot each year to prevent disease buildup.
• Pest and Disease Watch: Watch for signs of blight, scab, and insect pests. Remove affected foliage promptly, and avoid overhead watering.

What Is Hilling and Why Is It Important?

Hilling refers to the practice of mounding soil or mulch up along the base of the potato plants as they grow. This is done every few weeks, beginning as soon as shoots are several inches tall and continued throughout the bulk of the growing season.

• Prevents exposure of tubers to sunlight, which causes greening and bitterness.
• Discourages weed growth and conserves soil moisture.
• Encourages additional stolon production, potentially increasing yield.

Harvest and Storage Tips

• Allow tubers to remain in the ground for 1-2 weeks after the foliage dies back. This sets the skins, making them more durable for storage.
• Brush soil from potatoes, but avoid washing until just before use to prevent premature spoilage.
• Store in a cool (40-50°F/4-10°C), dark, and well-ventilated space. Avoid refrigeration, which turns starch to sugar.

Troubleshooting Common Potato Problems

• Green Potatoes: Caused by light exposure, leading to bitter, potentially toxic tubers. Prevent through regular hilling.
• Cracking and Hollow Centers: Typically from uneven watering or sudden rainfall after dry spells. Water consistently.
• Blight and Disease: Practice crop rotation and remove infected plants promptly. Use disease-resistant varieties when possible.

Frequently Asked Questions (FAQs)

How long does it take for potatoes to grow?

Depending on variety and conditions, potatoes require 10-20 weeks from planting to harvest. Early types mature in 10-12 weeks, while maincrops may take up to 20 weeks.

What is hilling, and how often should I do it?

Hilling means mounding soil or mulch around the stems to cover developing tubers. Start when plants are 6 inches tall, and repeat every 2-3 weeks or whenever new tubers approach the soil surface.

When should I stop watering my potatoes?

Once the foliage has mostly yellowed and died back, stop watering to help the tubers set their skins before harvest. This is usually in the last 1-2 weeks before lifting the crop.

Can I grow potatoes in containers or bags?

Absolutely. Grow bags and large containers are ideal for smaller spaces and make hilling and harvesting easier. Adjust the number of seed potatoes per container size for best results.

How do I know when potatoes are ready to harvest?

For new potatoes, harvest 2-3 weeks after flowering. For mature tubers, wait until foliage has fully died back and skins are toughened—typically 16-20 weeks after planting.

Summary: Cultivating a Bountiful Potato Harvest

Understanding each growth stage of the potato—from sprouting and leafy growth, through tuber initiation, bulking, and flowering, to natural senescence—empowers gardeners to time their care for optimal yields. By managing key practices like hilling, irrigation, and soil health, and by knowing when and how to harvest, you can enjoy abundant, flavorful potatoes from garden to table.

Author

medha deb

 

Medha Deb is an editor with a master's degree in Applied Linguistics from the University of Hyderabad. She believes that her qualification has helped her develop a deep understanding of language and its application in various contexts.

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