Getting Started

Start Seeds Inside:
Starting kohlrabi seeds indoors allows for controlled conditions and strong seedling development before transplanting outdoors. This helps you hit the cooler weather windows that kohlrabi prefers.

Direct Seed:
Direct seeding kohlrabi during the cooler months ensures plants can grow without the stress of high temperatures, which can negatively impact bulb development and flavor.

Transplant Starter Plants:
Transplanting kohlrabi starter plants from late fall through early spring helps them establish quickly and take advantage of the full cool-season growing period.

Kohlrabi is a reliable, compact crop that fits well into intensively planted beds. With the right timing and early care, it produces crisp, sweet bulbs and tender greens for a long harvest window.

Soil, Sun, Water, and Spacing

Soil:
Kohlrabi prefers well-drained, fertile soil with a pH between 6.0 and 7.5. Work in compost or well-rotted manure to improve fertility and structure and to support steady bulb growth.

Sun:
Full sun is ideal for kohlrabi, but it can tolerate partial shade, especially in warmer climates. In Zone 9, a bit of afternoon shade can help reduce heat stress during warm spells.

Watering:
Keep soil consistently moist but not waterlogged. Even moisture is especially important during bulb formation. Mulching helps retain soil moisture, suppress weeds, and regulate soil temperature.

Spacing:
Plant kohlrabi seeds 3–5 inches apart in rows spaced about 24 inches apart. Thin seedlings to 4–6 inches apart so each plant has enough room for proper bulb development.

Fertilization, Harvest, and Common Problems

Fertilization (N–P–K Ratio):
Kohlrabi benefits from a balanced fertilizer with moderate nitrogen to support leafy growth and bulb formation, such as 10-10-10 or 14-14-14, combined with plenty of organic matter.

When to Add:
Before Planting: Mix a balanced fertilizer into the soil before sowing or transplanting to promote strong initial growth.
Mid-Growing Season: Reapply every 4–6 weeks during the growing season to maintain steady growth and healthy bulbs.

Application Tips:

• Follow the directions on the fertilizer package to avoid over-fertilization.
• Apply fertilizer evenly around the base of plants, keeping it away from direct contact with stems.
• Water thoroughly after fertilizing to help nutrients move into the root zone.

Additional Tips:

• Build soil organic matter with compost to improve structure, drainage, and nutrient-holding capacity.
• Mulch to conserve moisture, suppress weeds, and keep bulbs cool and evenly hydrated.
• Keep growth steady—stops and starts from drought or poor nutrition can cause woody or split bulbs.

Harvesting:
Kohlrabi is ready to harvest when the bulbous stem reaches about 2–3 inches in diameter (around the size of a tennis ball), typically 50–80 days after planting. The bulbs should be firm; larger bulbs are more likely to become woody and less flavorful.

Pests and Diseases in Florida:

• Aphids: Small insects that suck sap from leaves and stems, causing curling and yellowing.
• Cabbage Worms: Caterpillars that chew large holes in leaves and can quickly defoliate plants.
• Flea Beetles: Tiny beetles that chew small “shot holes” in leaves and stress young plants.
• Cutworms: Caterpillars that sever young plants at the base, especially in freshly worked beds.
• Downy Mildew: Fungal disease that causes yellowing leaves with fuzzy, grayish growth on the underside.
• Clubroot: Soil-borne disease causing swollen, distorted roots and stunted growth.

Blog post on Natural Fertilizers

Natural Pest Control

Companion Plants and Plants to Avoid

Companion Plants:

Plants to Avoid Nearby: