How to Grow Kohlrabi in North Carolina

Kohlrabi is a unique and versatile vegetable that belongs to the Brassica family, which also includes cabbage, broccoli, and kale. Known for its crisp texture and mild flavor, kohlrabi can be enjoyed raw in salads, cooked in various dishes, or even fermented. For gardeners in North Carolina, growing kohlrabi can be a rewarding experience. This article will guide you through the essentials of cultivating kohlrabi in the Tar Heel State.

Understanding Kohlrabi

Before diving into the cultivation process, it’s essential to understand what kohlrabi is. This vegetable is characterized by its swollen stem that grows above ground, forming a bulbous shape that can range in color from pale green to purple. The leaves are large and leafy, resembling those of other brassicas.

Kohlrabi is rich in vitamins C and K, fiber, and antioxidants, making it a nutritious addition to your garden. It thrives in cooler temperatures, making it a perfect crop for spring and fall planting in North Carolina’s varied climate.

Choosing the Right Variety

When growing kohlrabi, selecting the right variety is crucial. In North Carolina’s diverse climate zones — ranging from USDA Hardiness Zones 7a to 8b — you have several options:

Green Kohlrabi: This variety has a mild flavor and is commonly found in grocery stores. It’s ideal for fresh consumption.
Purple Kohlrabi: This variety offers a slightly sweeter taste and adds visual appeal to your garden.
White Kohlrabi: Known for its crisp texture, this variety is well-suited for coleslaw and stir-fries.

Choose varieties based on your taste preferences and gardening style. If you’re new to kohlrabi, starting with a green or white variety may be best.

When to Plant Kohlrabi in North Carolina

Timing is critical when growing kohlrabi. In North Carolina, you can typically plant kohlrabi twice a year:

Spring Planting: Sow seeds indoors about 4-6 weeks before the last expected frost date (usually early to mid-April) or directly in the garden around the same time.
Fall Planting: Start seeds indoors again in late summer (around late July) for a fall crop that can be harvested before winter sets in.

Kohlrabi grows best when temperatures are between 50°F and 70°F. If planted during hotter months, it may bolt (go to seed) prematurely or develop a woody texture.

Preparing the Soil

Kohlrabi thrives in well-draining soil rich in organic matter. Here are steps you can take to prepare your garden bed:

Choose Location: Select a site that receives full sun (at least 6 hours of sunlight daily). Avoid areas prone to waterlogging.
Test Your Soil: Conduct a soil test to determine pH levels and nutrient content. Kohlrabi prefers slightly acidic to neutral soil pH (around 6.0 to 7.0).
Amend the Soil: Based on your soil test results, amend your soil with compost or well-rotted manure to improve fertility and drainage.
Tilling: Loosen the soil by tilling it to a depth of at least 12 inches. This aeration allows roots to grow freely.

Sowing Seeds

Once your soil is prepared, it’s time to sow seeds:

Direct Sowing: If you choose to plant seeds directly into the garden:
Create shallow furrows about ½ inch deep and space them 12-18 inches apart.
Sow seeds every 3-4 inches within the furrow.
Cover lightly with soil and water gently but thoroughly.
Transplanting Seedlings: If you started seeds indoors:
Harden off seedlings by gradually exposing them to outdoor conditions over a week.
Plant them outdoors once they have at least two true leaves and are around 3-4 inches tall.
Space transplants about 12 inches apart in rows spaced 18 inches apart.

Watering

Proper watering is vital for healthy kohlrabi growth:

Consistency: Keep the soil consistently moist but not waterlogged. Aim for about an inch of water per week, adjusting based on rainfall.
Mulching: Add a layer of mulch around plants after they are established to help retain moisture, suppress weeds, and regulate soil temperature.

Fertilization

Since kohlrabi is a hungry plant, proper fertilization will bolster its growth:

Before Planting: When preparing your bed, mix in compost as mentioned earlier.
During Growth: Apply a balanced fertilizer (like a 10-10-10 NPK) once plants reach about 6 inches tall. Follow package instructions for application rates.
Liquid Fertilizers: Consider using liquid fertilizers every few weeks during the growing season for an additional nutrient boost.

Pest and Disease Management

Like other members of the brassica family, kohlrabi can be susceptible to pests and diseases:

Common Pests

Cabbage Worms: These caterpillars can eat through leaves rapidly.
Control: Handpick them off plants or use organic insecticidal soap.
Aphids: Small sap-sucking insects that can lead to poor growth.
Control: Spray plants with water or treat with neem oil.

Common Diseases

Downy Mildew: A fungal disease that thrives in humid conditions.
Control: Ensure proper spacing between plants for airflow; avoid overhead watering.
Clubroot: A soil-borne disease affecting root development.
Control: Rotate crops annually and avoid planting brassicas in infected areas.

Harvesting Kohlrabi

Kohlrabi is usually ready for harvest between 50-70 days after sowing seedlings or transplanting:

The ideal size for harvesting is about 3-4 inches in diameter.
Use a sharp knife or garden shears to cut the bulb just above the soil line.
Remove any large leaves if necessary before storing.

For optimal taste and texture, harvest kohlrabi when it’s young; older bulbs may become tough and woody.

Storing Kohlrabi

After harvesting, store kohlrabi properly:

Refrigeration: Remove leaves (if attached) before placing bulbs in a perforated plastic bag or crisper drawer of your refrigerator.
Shelf Life: Fresh kohlrabi will last for up to two weeks when stored correctly.

Conclusion

Growing kohlrabi in North Carolina offers gardeners an exciting opportunity to experiment with this unique vegetable while enjoying its numerous health benefits. By understanding its requirements—from choosing the right variety and planting time to managing pests—your gardening experience can yield delicious results throughout both spring and fall seasons.

With patience and practice, you’ll soon find yourself with an abundant harvest of this crunchy cruciferous delight that’s sure to impress at your dinner table! Happy gardening!