How to Grow Kohlrabi Microgreens: A Complete Growing Guide
By Brian & Bryan, Microgreens Farmers & Founders of Wind River GreensKohlrabi microgreens are one of the most rewarding varieties to grow at home, offering a mild, sweet flavor with a subtle cabbage-like taste that's perfect for salads, sandwiches, and garnishes. These nutrient-dense greens are ready to harvest in just 7-14 days and provide an excellent source of vitamins A, C, and K, plus essential minerals like potassium and calcium.
Whether you're new to microgreens or looking to expand your growing repertoire, kohlrabi microgreens are forgiving, fast-growing, and incredibly satisfying to cultivate from seed to plate.
Photo by Judy Beth Morris on Unsplash
What Are Kohlrabi Microgreens?
Kohlrabi microgreens come from the same plant family as broccoli, cabbage, and kale (Brassicaceae). Unlike their full-grown counterparts that develop distinctive bulbous stems, kohlrabi microgreens are harvested as young seedlings with tender leaves and stems.
These microgreens typically display beautiful purple and green coloration, making them as visually appealing as they are nutritious. The flavor profile is mild and slightly sweet, without the sometimes bitter edge of mature kohlrabi.
At Wind River Greens, we've found kohlrabi microgreens to be one of our most popular varieties among customers who appreciate their versatility and consistent growing performance.
Essential Supplies for Growing Kohlrabi Microgreens
Before you begin growing, gather these essential materials:
Seeds: Purchase high-quality kohlrabi microgreen seeds from a reputable supplier. Look for organic, untreated seeds specifically labeled for microgreen production.
Growing trays: Use shallow trays with drainage holes (10" x 20" standard trays work well). You'll also need solid trays to catch drainage water.
Growing medium: Choose from coconut coir, peat moss, or a quality potting mix. Avoid garden soil, which can harbor harmful bacteria.
Weight: Use another tray or lightweight object to apply gentle pressure during the initial growing phase.
Water: Clean, filtered water is ideal. Avoid chlorinated tap water if possible.
Spray bottle: For gentle misting during early growth stages.
Sharp knife or scissors: For clean harvesting.
Step 1: Prepare Your Seeds
Kohlrabi seeds don't require pre-soaking, unlike larger seeds like sunflower or pea shoots. However, you can soak them for 2-4 hours in room temperature water to slightly speed up germination.
Measure out approximately 1-2 tablespoons of seeds per 10" x 20" tray. This density provides good coverage without overcrowding, which can lead to mold issues or weak growth.
If you choose to soak, drain the seeds thoroughly and let them sit in a strainer for about 30 minutes before planting. This prevents excess moisture that could cause problems during germination.
Step 2: Prepare Your Growing Medium
Fill your growing tray with about 1 inch of your chosen growing medium. The soil should be moist but not waterlogged – think of the consistency of a wrung-out sponge.
Level the surface gently with your hand or a small tool. You want an even, smooth surface that will provide consistent contact with your seeds.
If using coconut coir, make sure it's fully hydrated and fluffed. Pre-made potting mixes should be used straight from the bag, though you may want to remove any large chunks of bark or debris.
Step 3: Sow Your Kohlrabi Seeds
Scatter the kohlrabi seeds evenly across the prepared soil surface. Aim for good coverage without seeds overlapping significantly. The seeds should be touching or nearly touching but not piled on top of each other.
Gently press the seeds into the soil surface using your palm or a flat object. Don't bury them completely – they should still be visible but making good contact with the growing medium.
Mist the seeds lightly with your spray bottle. The goal is to dampen them without creating puddles or washing them around the tray.
Step 4: Create Blackout Conditions
Place a solid tray (without holes) directly on top of the seeded tray, creating darkness for the seeds. Add a light weight on top – another tray with a small book works perfectly.
This blackout period encourages strong stem development and prevents the seeds from trying to photosynthesize before they're ready. Keep the seeds in darkness for 3-4 days.
During this time, check daily for moisture levels. The soil should remain damp but not soggy. Mist lightly if needed, but be cautious not to overwater.
Step 5: Monitor Germination
After 2-3 days, you should see signs of germination. Kohlrabi seeds typically germinate quickly and uniformly under proper conditions.
Look for small white roots emerging from the seeds and the beginning of stem development. The seedlings will start pushing up against the covering tray.
Continue the blackout period until the seedlings are about 1 inch tall and beginning to lift the covering tray. This usually happens around day 4.
Step 6: Introduce Light
Remove the covering tray and weight once your kohlrabi microgreens have reached about 1 inch in height. The stems should appear pale or white – this is normal and expected.
Place the tray under your chosen light source. LED grow lights work excellently, but a sunny windowsill can also suffice if you live in an area with adequate natural light.
Position LED lights 12-18 inches above the microgreens. If using a windowsill, ensure the location receives at least 6 hours of indirect sunlight daily.
Step 7: Daily Care and Watering
Once exposed to light, kohlrabi microgreens develop quickly. Water from the bottom by adding water to the solid drainage tray rather than watering from above.
This bottom-watering method prevents mold and ensures the roots can access water without keeping the surface too wet. Add about 1/4 inch of water to the drainage tray and allow the soil to absorb it from below.
Check daily for water needs. The soil surface should be slightly moist but not soggy. In dry conditions, you might need to water daily, while humid environments may require watering every other day.
Step 8: Harvest Your Kohlrabi Microgreens
Kohlrabi microgreens are typically ready for harvest 7-14 days after sowing, depending on growing conditions and your preference for size. Look for well-developed cotyledon (seed) leaves and the emergence of the first true leaves.
The microgreens should be 1-2 inches tall with vibrant green and purple coloration. The stems should be crisp and the leaves should look fresh and healthy.
Use clean, sharp scissors or a knife to cut the microgreens just above the soil level. Cut only what you plan to use immediately for the best flavor and nutritional value.
Common Problems and Solutions
Mold growth: Usually caused by excessive moisture and poor air circulation. Reduce watering frequency and ensure your growing area has adequate ventilation.
Poor germination: Often due to old seeds, incorrect moisture levels, or temperature extremes. Use fresh seeds and maintain consistent moisture and temperature.
Leggy or weak growth: Typically results from insufficient light. Move your trays closer to your light source or increase daily light exposure.
Yellowing leaves: Can indicate overwatering or nutrient deficiency in the growing medium. Adjust watering schedule and consider using a nutrient-rich growing medium.
Storing and Using Kohlrabi Microgreens
Fresh kohlrabi microgreens can be stored in the refrigerator for 5-7 days. Place them in a sealed container with a paper towel to absorb excess moisture.
These versatile microgreens work beautifully in salads, sandwiches, wraps, and as garnishes for soups. Their mild flavor makes them appealing even to those who don't typically enjoy stronger brassica vegetables.
Try adding them to smoothies for a nutritional boost, or use them as a colorful topping for avocado toast. They also make excellent additions to stir-fries when added just before serving.
Common Mistakes to Avoid When Growing Kohlrabi Microgreens
Even experienced growers can encounter challenges with kohlrabi microgreens. Understanding these common pitfalls will save you time, money, and frustration while ensuring consistently successful harvests.
Overwatering During the Germination Phase
The most frequent mistake we see at Wind River Greens is overwatering during the first 3-4 days. Kohlrabi seeds need moisture to germinate, but excess water creates anaerobic conditions that promote damping-off disease and root rot. Instead of daily heavy watering, mist lightly every 12 hours or use the bottom-watering method by adding water to your drip tray and allowing the growing medium to absorb moisture from below.
Using Contaminated Equipment
Failing to sanitize your growing trays, scissors, and workspace leads to bacterial contamination that can destroy entire crops within 24-48 hours. Clean all equipment with a 10% bleach solution, rinse thoroughly, and allow to air dry before each use. This simple step prevents most growing problems before they start.
Harvesting Too Early or Too Late
Many growers harvest kohlrabi microgreens when they're still developing their true flavor profile around day 5-6, missing the optimal window. Wait until the cotyledons (seed leaves) are fully expanded and the first true leaves are just beginning to emerge, typically between days 8-12. Harvesting too late, after day 14, results in tougher stems and a more pronounced cabbage flavor that some find overwhelming.
Pro Tips from Experienced Growers
After years of perfecting our kohlrabi microgreen production, we've discovered several techniques that dramatically improve yields, flavor, and visual appeal.
The Double-Tray Stacking Method
For the first 48 hours after seeding, stack your growing tray inside another tray and place a third empty tray on top as a weight. This creates optimal germination conditions by maintaining consistent moisture and encouraging strong stem development. Remove the weight once you see the first green shoots pushing upward.
Temperature Cycling for Enhanced Color
To intensify the beautiful purple coloration in your kohlrabi microgreens, expose them to a 10-15°F temperature difference between day and night during the final 3-4 days before harvest. Keep them at 65-70°F during daylight hours and 50-55°F overnight. This stress response triggers anthocyanin production, creating more vibrant purple stems and leaves.
Strategic Light Management
Begin with 24 hours of darkness for the first 2-3 days, then gradually introduce light starting with 8 hours daily and increasing to 12-14 hours by day 5. Use full-spectrum LED lights positioned 6-8 inches above the trays. This progression creates stockier, more robust microgreens with better shelf life.
The "Dry Down" Technique
Reduce watering frequency during the final 2 days before harvest to concentrate flavors and improve storage life. The growing medium should feel barely moist to the touch. This technique also makes harvesting cleaner and reduces the risk of post-harvest wilting.
Troubleshooting Guide for Common Issues
Even with careful attention, you may encounter problems during your kohlrabi microgreen growing journey. Here's how to diagnose and resolve the most common issues quickly.
Poor Germination Rates (Less than 80%)
Symptoms: Patchy, uneven sprouting with large bare areas in your tray.
Causes and Solutions: Old seeds (over 2 years) lose viability rapidly. Test germination rates by placing 10 seeds on a damp paper towel for 5 days—you should see at least 8 sprouts. Temperature fluctuations also inhibit germination; maintain consistent 65-75°F conditions. Finally, seeds planted too deeply (more than ¼ inch) struggle to emerge, so barely cover with growing medium.
Leggy, Weak Growth
Symptoms: Tall, thin stems that fall over easily with pale green coloration.
Causes and Solutions: Insufficient light intensity or duration causes stretching as plants search for energy. Increase light exposure to 14-16 hours daily and move lights closer (4-6 inches from plants). Overcrowding also creates competition for light—reduce seeding density to 1 tablespoon per 10"x20" tray if necessary.
Mold Growth on Growing Medium
Symptoms: White, fuzzy growth on soil surface, distinct from normal root development.
Causes and Solutions: Excess moisture combined with poor air circulation creates ideal mold conditions. Improve ventilation with a small fan set on low speed, reduce watering frequency, and ensure your growing area stays between 65-72°F. Remove affected areas immediately with a clean spoon and increase spacing between trays.
Bitter or Off-Flavors
Symptoms: Harsh, unpleasant taste instead of the expected mild, sweet flavor.
Causes and Solutions: Stress from temperature extremes (above 80°F or below 55°F) triggers defensive compounds that create bitter flavors. Inconsistent watering also concentrates these compounds. Maintain steady environmental conditions and harvest during the optimal 8-12 day window before mature flavors develop.
Conclusion
Growing kohlrabi microgreens is an excellent introduction to microgreen cultivation, offering quick results and consistent success with minimal equipment. With proper attention to moisture, light, and timing, you'll be enjoying fresh, homegrown microgreens in less than two weeks. The satisfaction of growing your own nutrient-dense greens, combined with the delicious mild flavor of kohlrabi microgreens, makes this variety a perfect choice for both beginners and experienced growers alike.