How to Grow Kohlrabi in Wisconsin

Kohlrabi, a unique and versatile vegetable belonging to the cabbage family, is gaining popularity among home gardeners in Wisconsin. Known for its crisp texture and mild flavor, it can be eaten raw or cooked and adds a delightful crunch to salads and stir-fries. This article will guide you through the essential steps of growing kohlrabi in Wisconsin, from selecting the right variety to harvesting your crops.

Understanding Kohlrabi

Kohlrabi (Brassica oleracea var. gongylodes) is a biennial plant that is typically grown as an annual. It forms a swollen stem above the soil, which is the edible part of the plant, often confused with a root vegetable. The taste is similar to that of a broccoli stem or cabbage heart, making it an excellent addition to various dishes.

Varieties of Kohlrabi

When choosing the right variety of kohlrabi to grow in Wisconsin, consider factors such as local climate conditions and intended use. Some popular varieties include:

• Purple Vienna: This variety features a striking purple exterior and tender white flesh. It is known for its sweet flavor.
• White Vienna: A classic choice that produces round, pale green bulbs with crisp texture.
• Starburst: A hybrid variety that matures quickly and has a milder taste.

Climate Considerations

Wisconsin has a diverse climate that ranges from temperate to humid continental zones. Kohlrabi thrives in cool temperatures, making it an ideal crop for spring and fall planting. The optimal growing temperature for kohlrabi is between 55°F and 75°F. In Wisconsin’s climate, it’s essential to plan your planting timeline carefully.

Getting Started with Planting

Soil Preparation

Kohlrabi prefers well-drained soil rich in organic matter. The ideal pH level for kohlrabi is between 6.0 and 7.0. Here are the steps to prepare your soil:

1. Choose a sunny location: Select a spot that receives at least six hours of direct sunlight daily.
2. Test your soil: Use a soil testing kit to check pH levels and nutrient content.
3. Amend the soil: Based on your soil test results, add organic matter such as compost or well-rotted manure to improve fertility and drainage.
4. Tilling: Till the soil to a depth of about 12 inches to ensure good aeration.

Planting Seeds

You can start kohlrabi from seeds directly sown into the garden or by transplanting seedlings started indoors.

Direct Seeding

1. Timing: Sow seeds outdoors in early spring (mid-April) or late summer (early August) for fall harvest.
2. Seed Depth: Plant seeds about 1/2 inch deep in rows spaced 12-18 inches apart.
3. Thinning: Once seedlings are about 2 inches tall, thin them to 6-8 inches apart to allow for adequate growth.

Indoor Starting

1. Timing: Start seeds indoors 4-6 weeks before the last expected frost date for spring planting.
2. Transplanting: Harden off seedlings before transplanting them outdoors by gradually exposing them to outdoor conditions over a week.

Care and Maintenance

Once your kohlrabi plants are established, proper care will ensure healthy growth and robust yields.

Watering

Kohlrabi requires consistent moisture throughout its growing season:

• Frequency: Water deeply once or twice a week, depending on rainfall.
• Method: Use drip irrigation or soaker hoses to minimize water loss through evaporation and reduce leaf wetness, which can promote disease.

Fertilization

Kohlrabi benefits from balanced fertilization:

• Initial Fertilization: Incorporate a balanced fertilizer (like 10-10-10) into the soil at planting time.
• Side Dressing: Apply additional fertilizer when plants are about 6 inches tall to encourage leafy growth.

Pest and Disease Management

Kohlrabi can be susceptible to various pests and diseases:

• Pests: Watch out for aphids, cabbage worms, and flea beetles. Use row covers to prevent pests from reaching young plants and handpick any visible insects.
• Diseases: Fungal diseases like downy mildew can occur in humid conditions. Ensure good air circulation around plants and avoid overhead watering.

Harvesting Kohlrabi

Kohlrabi is typically ready for harvest 60 to 90 days after planting, depending on the variety:

1. Timing: Harvest when the bulbs reach about 3-4 inches in diameter for the best flavor and texture.
2. Method: Use a sharp knife to cut the bulb off just above the soil line. Leave some leaves intact as they can continue photosynthesis if you plan on leaving some bulbs in the ground longer.

Post-Harvest Care

After harvesting kohlrabi, proper storage will extend its shelf life:

• Storage Conditions: Store kohlrabi in a cool, dark place with high humidity (like a refrigerator).
• Shelf Life: Fresh kohlrabi can last up to two weeks when stored properly.

Culinary Uses of Kohlrabi

Once you’ve successfully grown your kohlrabi, it’s time to enjoy it! Here are some popular ways to prepare this nutritious vegetable:

• Raw: Peel and slice raw kohlrabi into sticks or rounds for salads or snacks.
• Cooked: Steam or sauté kohlrabi until tender; it pairs well with garlic and butter.
• Soups and Stews: Add diced kohlrabi to soups or stews for added texture and nutrition.

Conclusion

Growing kohlrabi in Wisconsin can be a rewarding experience that adds diversity to your garden and kitchen alike. By understanding the specific needs of this unique vegetable – from soil preparation and planting techniques to care, maintenance, and harvesting – you can successfully cultivate this delicious crop. With its crisp texture and mild flavor, kohlrabi offers endless culinary possibilities while contributing valuable nutrients to your diet. Embrace the challenge of growing this underrated vegetable; your taste buds will thank you!