How to Grow Kohlrabi Microgreens: Complete Step-by-Step Guide

Quick answer: You can grow kohlrabi microgreens at home in just 7-10 days, making them one of the quickest and most rewarding varieties to try. These mild, sweet greens are packed with vitamins C and K, and all you need to get started are quality seeds with an 85% or higher germination rate, a shallow 10x20 inch tray, and a growing medium like coconut coir. With the right setup, you'll have fresh, crunchy microgreens ready to enjoy in just over a week.

Kohlrabi microgreens are one of the most rewarding varieties to grow at home, offering a mild, sweet flavor with a subtle cabbage-like taste and beautiful purple stems. These nutrient-dense greens are packed with vitamins C and K, antioxidants, and essential minerals, making them a fantastic addition to salads, sandwiches, and smoothies.

Growing kohlrabi microgreens is surprisingly simple and takes just 7-10 days from seed to harvest. With the right setup and technique, you'll have fresh, crunchy microgreens ready to enhance your meals in just over a week.

What You'll Need to Get Started

Before diving into the growing process, gather these essential supplies for successful kohlrabi microgreen cultivation.

Seeds and Growing Medium

Choose high-quality kohlrabi seeds specifically labeled for microgreen production. These seeds should be untreated and have a high germination rate of 85% or higher.

For growing medium, you have several excellent options. Coconut coir provides excellent moisture retention and drainage, while peat moss offers similar benefits with slightly different texture. Seed starting mix works well too, or you can try soilless options like hemp mats or paper towels for a cleaner growing experience.

Containers and Equipment

You'll need shallow growing trays with drainage holes, typically 1-2 inches deep. Standard 10x20 inch seed starting trays work perfectly for home growing.

A spray bottle is essential for gentle watering, and you'll want a solid tray underneath to catch excess water. Consider getting a humidity dome or clear plastic cover for the germination phase.

Step-by-Step Growing Process

Follow these detailed steps to grow healthy, flavorful kohlrabi microgreens from start to finish.

Step 1: Prepare Your Growing Medium

Fill your growing tray with about 1 inch of your chosen growing medium. The medium should be moist but not waterlogged – think of a wrung-out sponge consistency.

Level the surface gently with your hands, creating an even bed for your seeds. Avoid compacting the medium too much, as kohlrabi seeds need some air circulation around them to germinate properly.

Step 2: Sow the Seeds

Kohlrabi microgreens require a seeding rate of about 1-2 ounces per 10x20 inch tray. This might seem like a lot, but kohlrabi seeds are relatively large compared to varieties like broccoli or alfalfa.

Sprinkle the seeds evenly across the prepared surface. Don't worry about perfect spacing – microgreens grow well when slightly crowded. Gently press the seeds into the growing medium with your hand or a flat tool, ensuring good seed-to-soil contact.

Step 3: Initial Watering and Covering

Mist the seeded tray thoroughly with your spray bottle, ensuring all seeds are moistened. The surface should be damp but not flooding.

Cover the tray with another tray (upside down) or a humidity dome to create darkness and maintain moisture. This blackout period is crucial for proper germination. Place a light weight on top if using an inverted tray.

Step 4: Germination Phase (Days 1-3)

Keep your covered trays in a location with temperatures between 65-75°F (18-24°C). Kohlrabi seeds typically germinate within 24-48 hours under these conditions.

Check daily by lifting the cover briefly. Mist lightly if the surface appears to be drying out, but avoid overwatering which can lead to mold issues.

You'll start seeing tiny white root hairs and the first signs of stems pushing up by day 2 or 3.

Step 5: Transition to Light (Days 4-5)

Once you see stems reaching about half an inch tall and some are starting to push against the cover, it's time to remove the blackout covering.

Move your tray to a location with bright, indirect light or under grow lights. At Wind River Greens, we've found that kohlrabi microgreens thrive under LED grow lights placed 12-18 inches above the trays.

Continue misting 1-2 times daily, keeping the growing medium consistently moist but not soggy.

Step 6: Growth and Development (Days 6-8)

During this phase, you'll see rapid development. The distinctive purple stems of kohlrabi microgreens will start showing color, and the first true leaves will begin forming.

Water from the bottom now by adding water to your catch tray rather than misting from above. This prevents water from sitting on the leaves and reduces disease risk.

Monitor for any signs of mold or fungal issues, which appear as fuzzy white or gray growth. Good air circulation helps prevent these problems.

Step 7: Final Growth and Harvest Preparation (Days 9-10)

Your kohlrabi microgreens are nearly ready when they reach 2-3 inches tall with well-developed cotyledon leaves. The stems should show good purple coloration, and the leaves should appear healthy and vibrant.

Stop bottom watering 12-24 hours before harvest to reduce moisture content and extend shelf life after cutting.

Harvesting Your Kohlrabi Microgreens

Timing your harvest correctly ensures the best flavor and nutritional content from your kohlrabi microgreens.

When to Harvest

Kohlrabi microgreens are typically ready 7-10 days after sowing, depending on growing conditions and desired size. Look for microgreens that are 2-3 inches tall with fully opened cotyledon leaves.

The ideal harvest time is when the first true leaves are just beginning to emerge but haven't fully developed. At this stage, the flavor is mild and sweet with just a hint of the characteristic kohlrabi taste.

Harvesting Technique

Use sharp, clean scissors or a knife to cut the microgreens about 1/4 inch above the growing medium. Cut in small sections rather than trying to harvest the entire tray at once.

Harvest only what you need immediately, as fresh-cut microgreens have the best flavor and nutritional value. The remaining microgreens will continue growing slowly and can be harvested over the next few days.

Storage and Usage Tips

Proper storage extends the life of your fresh kohlrabi microgreens and maintains their crisp texture and mild flavor.

Storage Methods

Store harvested kohlrabi microgreens in the refrigerator in a breathable container or plastic bag with small holes. They typically stay fresh for 5-7 days when stored properly.

Avoid washing the microgreens until just before use, as excess moisture can lead to faster spoilage. If you must wash them, pat completely dry with paper towels before storing.

Culinary Uses

Kohlrabi microgreens have a mild, slightly sweet flavor that works beautifully in fresh applications. Add them to salads for color and crunch, use as a garnish for soups, or layer them in sandwiches and wraps.

Try incorporating them into smoothies for added nutrition without overwhelming flavor, or use them as a colorful topping for avocado toast. Their purple stems make them particularly attractive as a garnish for special dishes.

Troubleshooting Common Issues

Even with careful attention, you might encounter some challenges when growing kohlrabi microgreens. Here's how to address the most common problems.

Poor Germination

If your seeds aren't germinating well, check the seed age and storage conditions first. Old or improperly stored seeds will have reduced viability.

Temperature is crucial – kohlrabi seeds need consistent warmth to germinate. If your growing area is too cool, consider using a heating mat to maintain optimal temperature.

Mold and Fungal Issues

White fuzzy growth on your growing medium or stems indicates mold problems. This usually results from too much moisture, poor air circulation, or contaminated seeds or growing medium.

Increase ventilation, reduce watering frequency, and ensure you're using clean tools and containers. Sometimes starting over with fresh, sterile supplies is the best solution.

Leggy or Weak Growth

If your kohlrabi microgreens are growing tall and spindly with pale color, they likely need more light. Move them closer to your light source or increase daily light exposure.

Weak stems can also indicate overwatering or poor air circulation. Adjust your watering schedule and ensure good airflow around your growing trays.

Maximizing Your Success

A few advanced tips can help you consistently grow premium kohlrabi microgreens with excellent flavor and appearance.

Seed Quality and Testing

Always source seeds from reputable suppliers and test germination rates before committing to large batches. A simple test involves placing 10 seeds on a damp paper towel in a sealed container for 48 hours to check sprouting percentage.

Store seeds in a cool, dry place and use within 2-3 years for best results. Proper seed storage significantly impacts your success rate.

Environmental Control

Maintaining consistent temperature and humidity creates optimal growing conditions. Aim for 65-75°F during the day with slightly cooler nighttime temperatures.

Good air circulation prevents many common problems while supporting healthy growth. A small fan on low speed can provide gentle air movement without disturbing the developing microgreens.

Growing kohlrabi microgreens is an rewarding way to add fresh, nutritious greens to your diet year-round. With their quick growing time, mild flavor, and beautiful appearance, they're perfect for both beginners and experienced growers. Following these detailed steps will help ensure your success and provide you with delicious, homegrown microgreens in just over a week. Remember that like any skill, growing microgreens improves with practice, so don't be discouraged if your first attempts aren't perfect – each growing cycle teaches you something new about creating the ideal conditions for these remarkable little plants.

Other articles from the farm

1. Microgreens 101: Everything You Need to Know
2. Explore All Microgreen Varieties (Plant Database)
3. Recipe: Sunflower Microgreen Salad
4. Recipe: Microgreen Pesto

What It Actually Costs to Grow Kohlrabi Microgreens at Home

One of the real advantages of growing kohlrabi microgreens is that the ongoing cost is low once you have your basic setup. Here's a realistic breakdown so you know what to expect before you start spending money.

A pound of quality kohlrabi microgreen seeds typically runs between $8 and $15, depending on the supplier. One pound is enough to plant roughly 8 to 12 trays, which means your seed cost per tray comes out to about $1.00 to $1.75. That's a meaningful savings compared to buying pre-grown microgreens at a farmers market or grocery store, where a 2-ounce clamshell can cost $5 to $8.

One-Time Startup Costs

• 10x20 inch growing trays (set of 5): $10–$20
• Humidity dome or clear plastic cover: $5–$10
• Spray bottle: $3–$6
• Coconut coir brick (expands to fill multiple trays): $8–$12
• Small kitchen scale for measuring seed weight: $10–$15

Total startup investment usually lands between $35 and $65. After that, your main recurring costs are seeds and growing medium. A single coconut coir brick typically yields enough material for 10 to 15 trays, so your medium cost per tray is minimal — often under $1.00.

If you plan to grow consistently, buying seeds in bulk (1 lb or more) drops your per-tray cost noticeably. Suppliers like True Leaf Market and Johnny's Selected Seeds both carry kohlrabi microgreen seeds in bulk quantities and tend to offer better germination rates than random packets found in hardware stores.

Adjusting Your Grow for Different Seasons

Kohlrabi microgreens are fairly forgiving across seasons, but temperature swings in your home can affect germination speed and final flavor. Knowing what to adjust helps you get consistent results year-round.

The ideal germination temperature is between 65°F and 75°F. During summer, most homes stay within this range without much effort. In winter, rooms can dip below 60°F overnight, which slows germination from the typical 2 to 3 days to 4 to 5 days. This isn't a crisis — the seeds will still germinate — but if you're on a tight schedule, consider placing your tray on top of a refrigerator or near a heat source during the blackout phase to maintain warmth.

Summer Growing Tips

Heat is the bigger challenge in summer. Temperatures consistently above 80°F can cause kohlrabi microgreens to bolt quickly or develop a slightly bitter edge before they're ready to harvest. If your growing space gets warm, move trays away from south-facing windows and water more frequently — once in the morning and once in the evening — to keep the medium from drying out. Harvesting promptly at the cotyledon stage matters more in warm weather; waiting an extra day or two can push the flavor in a direction you don't want.

Winter Growing Tips

Low light in winter is a real factor. Kohlrabi microgreens need 4 to 6 hours of good light daily after they're uncovered. Natural light from a window may not cut it in December or January depending on your location. A basic LED grow light positioned 2 to 4 inches above the tray for 12 to 14 hours per day solves this without much complexity or cost. Entry-level grow lights suitable for a few trays run $20 to $40 and last for years.

Common Mistakes That Affect Your Results

Most failed or disappointing kohlrabi microgreen grows come down to a handful of recurring issues. Avoiding these will put you well ahead.

Overwatering during germination. The growing medium should stay moist, not wet. Standing water around seeds invites mold — a particular concern with brassica varieties like kohlrabi. If you see white fuzz on the medium surface shortly after sowing, it's almost always a moisture problem rather than a disease issue. Let the surface dry slightly between waterings and make sure your drainage tray isn't holding excess water underneath.

Skipping the weight during blackout. Placing a weighted tray on top of your seeds during the blackout phase encourages strong, even root development. Without it, kohlrabi seeds often produce uneven germination with some seeds failing to anchor properly. A second empty tray with a few filled water bottles on top applies enough pressure without crushing the seeds.

Harvesting too late. Kohlrabi microgreens are best cut at the cotyledon stage — when the two seed leaves are fully open and before the first true leaves appear. This usually happens between day 7 and day 10. Once true leaves emerge, the stems become slightly tougher and the mild sweetness gives way to a more pronounced bitter note that not everyone enjoys.

Using treated seeds. Seeds treated with fungicides or other coatings are not safe for microgreen production. Always confirm your seeds are labeled as untreated before use. When in doubt, contact the supplier directly — reputable seed companies will tell you clearly.