Growing Kohlrabi: Tips for a Healthy, Productive Harvest

Growing Kohlrabi
Growing kohlrabi rewards gardeners who start seeds early indoors, transplant into fertile, moist soil, and space plants generously. Cooler temperatures sweeten its crisp bulbs, meaning spring and fall plantings yield superior harvests. With plenty of sunlight, timely watering and regular feeding, cultivating this funky brassica becomes a deliciously satisfying experience—read on for exactly how to maximize your kohlrabi crop.
🌱 Kohlrabi Growing Cheatsheet: Maximize Your Harvest
🌤️ Ideal Growing Conditions
- ☀️ Full sun, ≥6 hrs/day
- 🌡️ Optimal temp: 50-75°F (10-24°C)
- 🌱 Rich, well-draining soil; pH 6.0-7.5
📅 Timing & Planting
- 🗓️ Start indoors 4-6 weeks pre-last frost or direct sow early spring/fall
- 🌱 Plant seeds ¼ inch (0.6 cm) deep, spaced 4-6 inches (10-15 cm) apart
- 🛤️ Rows: 12-18 inches (30-45 cm) apart
💧 Watering & Maintenance
- 🚿 Water consistently, 1-1.5 inches (2.5-4 cm) weekly
- 🌾 Mulch to retain moisture, prevent weeds
- ✂️ Thin seedlings after 2 true leaves appear
🍃 Fertilizing
- 🌿 Apply compost or balanced fertilizer (10-10-10) at planting
- 🔄 Side-dress with compost mid-season for vigorous growth
🐛 Pest & Disease Control
- 🐞 Inspect regularly; handpick caterpillars, aphids immediately
- 🧅 Rotate crops yearly; avoid cabbage-family crops in same area for 3 years
🥦 Harvest Tips for Maximum Yield
- 📏 Harvest bulbs at 2-3 inches (5-7.5 cm) diameter for optimal taste, texture
- 🔪 Cut bulb at base; leaves edible, nutritious source of Vitamins C, A, K
- ❄️ Store bulbs refrigerated (0-4°C / 32-39°F), lasts up to a month
🥗 Health & Self-Sufficiency Benefits
- 💪 Rich in antioxidants, dietary fiber, potassium for improved wellness
- 🌿 High-yield crop suitable for urban gardens and sustainable food production

Choosing Kohlrabi Varieties Wisely
I remember my first time growing kohlrabi. I chose a random variety without much thought, resulting in slightly undersized bulbs despite my best efforts.
Careful selection pays off immensely. For stellar yields, aim for reliable varieties like 'Early White Vienna' or 'Purple Vienna'—both deliver uniform bulbs in roughly 55–60 days.
Timing and Soil Preparation Spell Success
Like most veggies, timing your planting makes or breaks your kohlrabi harvest. This curious brassica thrives in chilly weather between 40–75°F (5–24°C).
Over the years, I've found sowing seeds directly outside in early spring—2 weeks before your area's last frost date—is ideal. For fall harvests, mid-to-late summer planting (60–70 days before frost arrives) hits the sweet spot.
Rich, fluffy soil is everything. Work in ample compost beforehand, ideally achieving a slightly acidic to neutral soil (6.0–7.0 pH).
"Well-composted soil increases your kohlrabi's yield potential by over 25%."
Proper Spacing and Planting Techniques
Kohlrabi prefers breathing room—I've learned the hard way that crowding leads to disappointingly small bulbs. Space plants every 6–8 inches (15–20 cm) apart with at least 12–18 inches (30–45 cm) between rows.
Sow seeds about ¼ to ½ inch (0.6–1.3 cm) deep. After germination—usually a painless 7–10 days—thin carefully to avoid disturbing neighboring seedlings.
Watering Practices for Juicy Kohlrabi
Kohlrabi bulbs swell best when consistently hydrated. Aim to deliver at least 1 to 1½ inches (2.5–3.8 cm) of water per week, preferably early in the morning to limit evaporation.
Mulching around each plant with straw or shredded leaves keeps moisture steady and curbs weed growth. Personally, I'm partial to chopped straw—it breaks down neatly into the soil later in the season.
Feeding and Fertilizing for Optimal Growth
Though kohlrabi isn't overly demanding, regular feeding works wonders. Once seedlings have developed their first true leaves, fertilize using an organic balanced fertilizer—something like fish emulsion or seaweed extract works beautifully.
A light side-dressing of compost or aged manure halfway through the growing season provides a timely boost, pushing bulbs from "average" to "spectacular."
Troubleshooting Common Kohlrabi Problems
Every gardener encounters a few setbacks, and kohlrabi is no exception. Two pests consistently cause me mild annoyance: cabbage worms and aphids.
- Cabbage worms: Inspect regularly and handpick these munchers off your plants. Row covers installed at planting time significantly reduce infestations.
- Aphids: Spray plants with a gentle stream of water or use insecticidal soap solutions to knock aphids back before they establish colonies.
Harvest at Peak Perfection
Knowing the ideal harvest time is essential. Aim to harvest bulbs when they're about golf ball to tennis ball sized—typically between 2–3 inches (5–7.5 cm) across.
Waiting too long results in woody, fibrous bulbs—something I've sadly tasted once too often. Gather promptly, cut at soil level and savor the crisp, subtly sweet flavor right away—or refrigerate bulbs wrapped loosely in damp towels for weeks of storage.
"A timely-picked bulb means maximum tenderness and flavor—delay at your peril."
Frequently Asked Questions About Growing Kohlrabi
What soil supports healthy kohlrabi plant growth?
Kohlrabi thrives in fertile, well-draining soil that stays consistently moist and provides ample nutrients. Adding organic matter, such as compost or aged manure, encourages steady bulb development and vigorous growth.
How much sunlight does kohlrabi require?
For optimal bulb development, ensure your plants receive a minimum of six hours of direct sunlight daily. While kohlrabi adapts to partial shade, less sunlight typically results in smaller bulbs and slower maturation.
What's the ideal spacing between kohlrabi plants?
Proper spacing strongly influences bulb size and yield. Allow about 6 to 8 inches (15 to 20 cm) between each plant and keep rows spaced 12 to 18 inches (30 to 45 cm) apart, providing sufficient room for mature bulb growth.
When is the best planting period for growing kohlrabi?
Kohlrabi prefers cool weather, making it ideal for planting in early spring or late summer. For steady growth, plant seeds outdoors when temperatures range consistently between 40 to 75°F (4 to 24°C).
How frequently does kohlrabi require watering?
Maintain consistently moist soil by watering your kohlrabi plants approximately 1 to 1.5 inches (2.5 to 3.8 cm) per week, adjusting as needed based on rainfall. Regular watering prevents cracking and results in uniform bulb growth.
What methods help prevent pests on kohlrabi plants?
Implement pest prevention by using floating row covers to block insects without hindering sunlight and moisture. Crop rotation and companion planting with herbs such as dill or mint also deter common pests like cabbage worms and aphids.
How do I know when to harvest kohlrabi?
The ideal harvesting stage arrives once bulbs reach a diameter of about 2 to 4 inches (5 to 10 cm). Smaller bulbs prove tender and flavorful, whereas larger bulbs may turn tough and fibrous. Harvest promptly upon reaching the desired size by cutting just below the bulb base.
Growing kohlrabi asks little but gives generously. With good sun, healthy soil, steady moisture, and smart spacing, you'll harvest crisp, flavorful bulbs worth savoring. Careful timing—planting early in spring or late summer—ensures quick, steady maturity. Keep weeds and pests in check, and your kohlrabi rewards you handsomely. Remember, this humble vegetable offers flavor and abundance to anyone willing to give it proper care and attention.
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