Growing Hydroponic Kohlrabi: Crispy Crunchy Bulbs Indoors

Why Grow Kohlrabi Hydroponically?

Kohlrabi is one of the fastest-growing brassicas, producing crispy, mild-flavored bulbs in just 55-65 days. Hydroponic cultivation yields exceptionally tender bulbs without the woodiness that sometimes affects soil-grown kohlrabi.

The unique "alien spaceship" appearance makes kohlrabi a conversation starter, and its versatility in the kitchen—raw, roasted, or stir-fried—makes it worth growing.

What You'll Need

• NFT system with 4-inch channels
• Nutrient solution balanced for leafy brassicas
• pH meter (maintain 6.0-6.8)
• Growing medium like rockwool or clay pebbles
• Adequate lighting for 12-14 hours daily

Use our plant spacing calculator for optimal arrangement.

Step-by-Step Growing Guide

1. Days 1-10: Germinate seeds in starter plugs at 65-75°F
2. Days 11-20: Transplant seedlings when they have 3-4 true leaves
3. Days 21-40: Bulb formation begins - maintain consistent nutrient flow
4. Days 41-55: Rapid bulb expansion - harvest when 2-3 inches diameter
5. Days 56-65: Extended harvest window for larger bulbs up to 4 inches

Common Mistakes to Avoid

• Letting bulbs get too large: Becomes woody and fibrous past 4 inches
• Inconsistent watering: Causes cracking in the bulb
• Too much nitrogen: Promotes leaves over bulb development
• Crowding plants: Reduces bulb size and quality

Pro Tips for Maximum Success

• Grow both purple and green varieties for visual interest
• Harvest leaves too—they're edible and nutritious like collard greens
• Maintain cool temperatures (60-70°F) for sweetest flavor
• Succession plant every 2 weeks for continuous harvest