How to Look After Potatoes: A Comprehensive Guide for Healthy Growth and a Bountiful Harvest

Potatoes are one of the most popular and versatile crops for home gardeners, providing a delicious, nutrient-rich staple food. However, successfully growing and caring for potatoes requires knowledge of their unique needs. This comprehensive guide will take you through everything you need to know about how to look after potatoes, from selecting the right variety and preparing the soil to watering, fertilizing, and dealing with common pests and diseases. Whether you’re a seasoned gardener or a beginner, these expert tips will ensure a healthy and bountiful potato harvest.

1. Types of Potatoes

Before you start planting, it’s essential to choose the right type of potato for your garden and culinary needs. Potatoes come in several varieties, and understanding the differences can help you make the best selection.

1.1. First Early Potatoes

First early potatoes are the quickest to mature, usually within 10-12 weeks of planting. They are smaller in size and ideal for new potatoes. Popular first early varieties include:

• ‘Rocket’
• ‘Swift’
• ‘Pentland Javelin’

1.2. Second Early Potatoes

Second early potatoes take about 14-16 weeks to mature. They are slightly larger than first early potatoes and can be used as salad potatoes. Common varieties include:

• ‘Charlotte’
• ‘Kestrel’
• ‘Maris Peer’

1.3. Maincrop Potatoes

Maincrop potatoes are planted later in the season and take 18-20 weeks to mature. These potatoes are larger, store well, and are perfect for baking, mashing, and frying. Maincrop varieties include:

• ‘Maris Piper’
• ‘Desiree’
• ‘King Edward’

2. Preparing the Soil for Potatoes

Potatoes grow best in well-draining, loose, and slightly acidic soil with a pH between 5.0 and 6.5. Proper soil preparation is crucial for healthy plants and a successful harvest.

2.1. Soil Type

Potatoes thrive in loamy or sandy soil, which allows their tubers to develop without being restricted. Avoid heavy clay soil, as it can cause poor drainage and lead to rotting tubers. If you have clay soil, consider planting potatoes in raised beds or containers filled with lighter soil.

2.2. Soil Amendments

To improve the soil’s fertility, work in plenty of organic matter, such as compost or well-rotted manure, before planting. This boosts the soil’s structure, improves drainage, and provides essential nutrients for potato growth.

2.3. Fertilization

Potatoes are heavy feeders, meaning they require a nutrient-rich environment to thrive. Before planting, add a balanced fertilizer, such as 10-10-10, to the soil. Focus on phosphorus and potassium, which support root and tuber development. Avoid excess nitrogen, which can lead to lush foliage at the expense of tuber growth.

3. Planting Potatoes

Planting potatoes at the right time and in the right way is key to their success. Potatoes prefer cool temperatures, so early spring is the best time to plant them.

3.1. When to Plant Potatoes

Potatoes should be planted in early spring, about 2-4 weeks before the last expected frost date. The soil temperature should be at least 7°C (45°F) to ensure good germination and growth. You can stagger planting to extend the harvest season by planting early, second early, and maincrop varieties at different times.

3.2. Preparing Seed Potatoes

Instead of planting whole potatoes, gardeners use seed potatoes, which are certified disease-free tubers. To prepare your seed potatoes:

1. Cut larger seed potatoes into pieces, ensuring each piece has at least one or two “eyes” (sprouts).
2. Allow the cut pieces to cure for a day or two before planting. This helps prevent rot by forming a callous over the cut surface.

3.3. Planting Depth and Spacing

• Plant Depth: Plant potatoes about 10-15 cm (4-6 inches) deep.
• Spacing: Space potato plants about 30 cm (12 inches) apart in rows that are about 60 cm (24 inches) apart.

For container planting, fill the container with about 10-15 cm (4-6 inches) of soil, place the seed potatoes, and cover them with another 10 cm (4 inches) of soil.

4. Watering Potatoes

Proper watering is essential for potato growth, particularly during tuber formation. Too little water can lead to small, misshapen tubers, while too much water can cause rot and disease.

4.1. Watering Frequency

Potatoes need about 2.5 cm (1 inch) of water per week. Keep the soil consistently moist but not waterlogged. Water early in the morning to allow the foliage to dry before evening, reducing the risk of fungal diseases.

4.2. Watering Tips

• Avoid Overhead Watering: Use a soaker hose or drip irrigation to water the soil directly and prevent the leaves from getting wet. Wet foliage can lead to blight and other fungal diseases.
• Increase Watering During Tuber Formation: When the plants start to flower, they are entering the tuber formation stage. This is when potatoes require the most water, so increase your watering frequency during this period.

5. Hilling Potatoes

Hilling is an essential process for growing potatoes and involves mounding soil around the base of the plants. This encourages tuber growth and prevents the potatoes from being exposed to sunlight, which can turn them green and toxic.

5.1. How to Hill Potatoes

Once the potato plants reach about 15-20 cm (6-8 inches) tall, start mounding soil around the base of the plants, covering about one-third of the stems. Repeat the process every couple of weeks as the plants grow, eventually creating a mound that is about 30 cm (12 inches) high.

5.2. Benefits of Hilling

• Prevents Green Potatoes: Exposure to sunlight can cause the potatoes to turn green and produce solanine, a toxic substance. Hilling keeps the developing tubers covered.
• Increases Yield: Hilling encourages the plants to produce more tubers by providing more soil for them to grow in.

6. Fertilizing Potatoes During Growth

While potatoes are heavy feeders, over-fertilizing can result in too much leafy growth and fewer tubers. It’s essential to feed your plants the right nutrients at the right time.

6.1. Side-Dressing with Fertilizer

After hilling, side-dress the plants with a balanced fertilizer, such as 5-10-10. Apply the fertilizer along the sides of the rows or around the base of the plants. Be careful not to let the fertilizer come into direct contact with the plants, as this can cause burning.

6.2. Compost Tea

Another excellent way to provide nutrients to your potato plants is by using compost tea, which can be applied as a foliar spray or watered into the soil. Compost tea provides essential micronutrients and boosts plant immunity.

7. Pest and Disease Control for Potatoes

Potatoes are susceptible to a variety of pests and diseases, but with proper care and attention, you can minimize these problems and keep your plants healthy.

7.1. Common Potato Pests

• Colorado Potato Beetle: These yellow and black-striped beetles feed on potato leaves and can quickly defoliate a plant. Hand-pick beetles and their larvae from the plants and use organic insecticides if necessary.
• Aphids: Small, soft-bodied insects that suck the sap from potato plants. Use insecticidal soap or introduce beneficial insects like ladybugs to control aphid populations.
• Wireworms: The larvae of click beetles, which can damage developing tubers by boring into them. Use crop rotation and trap crops to reduce wireworm infestations.

7.2. Common Potato Diseases

• Potato Blight: A fungal disease that causes dark, water-soaked spots on leaves and stems. Blight thrives in wet, humid conditions, so avoid overhead watering and ensure good air circulation. Use resistant varieties and apply fungicides if necessary.
• Scab: A bacterial disease that causes rough, corky patches on the surface of the tubers. Scab is more common in alkaline soils, so maintain a slightly acidic pH and avoid fresh manure when planting.
• Verticillium Wilt: A soil-borne disease that causes yellowing and wilting of the lower leaves. Rotate crops and avoid planting potatoes in the same spot for more than two years to reduce the risk of wilt.

8. Harvesting Potatoes

The timing and method of harvesting potatoes depend on the type of potato you are growing. Early varieties can be harvested while still small, while maincrop potatoes should be left in the ground until fully mature.

8.1. When to Harvest Potatoes

• Early Potatoes: Harvest early potatoes about 10-12 weeks after planting, once the flowers appear. These potatoes are smaller and best enjoyed fresh.
• Maincrop Potatoes: Wait until the foliage dies back before harvesting maincrop potatoes, usually around 18-20 weeks after planting. This allows the skins to thicken, making them better for storage.

8.2. How to Harvest

Use a garden fork to

carefully lift the plants, starting from the edges to avoid damaging the tubers. Shake off the soil and allow the tubers to dry for a few hours before storing.

9. Storing Potatoes

Proper storage is essential to prevent potatoes from spoiling or sprouting.

9.1. Curing Potatoes

After harvesting, cure potatoes by leaving them in a cool, dark, and well-ventilated area for about 10-14 days. This toughens their skin and helps them store longer.

9.2. Long-Term Storage

Store cured potatoes in a dark, cool, and humid environment, ideally at temperatures between 7-10°C (45-50°F). Avoid storing them near onions, as the gases they emit can cause the potatoes to spoil.

Conclusion

Looking after potatoes requires attention to detail, from soil preparation and planting to watering, fertilizing, and pest control. By following these steps, you’ll be well on your way to enjoying a bountiful potato harvest. With the right care, your potato plants will thrive, providing you with delicious tubers for months to come. Happy gardening!

Find all our September Monthly gardening and allotment jobs here