From Seed to Harvest: Essential Tips for How to Plant Kohlrabi Seeds Indoors Successfully

Kohlrabi, with its unique bulbous stems and sweet, slightly nutty flavor, is a delicious addition to any garden. But did you know you can enjoy this crunchy vegetable even sooner by starting your kohlrabi seeds indoors? This guide will walk you through the process of planting kohlrabi seeds indoors, ensuring a bountiful harvest in no time.

Why Start Kohlrabi Seeds Indoors?

Starting kohlrabi seeds indoors offers several advantages:

• Earlier Harvest: Get a jump on the growing season and enjoy fresh kohlrabi weeks earlier than direct sowing.
• Control over Environment: Provide ideal growing conditions for your seedlings, protecting them from harsh weather and pests.
• Thinner, Healthier Plants: Indoor starting allows for more space for seedlings to develop strong roots and healthy stems.

Choosing the Right Seeds and Planting Time

Seed Selection:

• Variety: Choose varieties that are specifically bred for indoor starting. Look for “quick-maturing” or “early-maturing” varieties like “Early White Vienna” or “Purple Vienna.”
• Quality: Opt for fresh, high-quality seeds from reputable suppliers.

Planting Time:

• Timing: Kohlrabi seeds can be sown indoors 6-8 weeks before your last frost date. This ensures the seedlings are ready to be transplanted outdoors when the weather is warm enough.
• Region: Consult your local gardening calendar or online resources to determine the optimal planting time for your specific region.

Preparing for Indoor Seed Starting

1. Gather Your Supplies:

• Seed Starting Trays: Choose trays with drainage holes and individual cells for each seedling.
• Seed Starting Mix: Use a sterile, peat-based seed starting mix designed for indoor use.
• Watering Can with a Fine Rose: This allows for gentle and controlled watering.
• Grow Lights: Provide supplemental light for seedlings, especially in low-light conditions.
• Heat Mat (Optional): A heat mat can help maintain a consistent temperature for optimal germination.

2. Sterilize Your Supplies:

• Trays: Wash trays with soap and water, then sterilize them with a bleach solution (1 part bleach to 9 parts water). Rinse thoroughly.
• Tools: Sterilize any tools you’ll be using, like a trowel or potting spoon, with rubbing alcohol.

3. Prepare the Seed Starting Mix:

• Moistening: Moisten the seed starting mix thoroughly, ensuring it’s evenly damp but not soggy.
• Filling Trays: Fill the individual cells in the trays with the moistened mix, leaving about ½ inch of space at the top.

Sowing the Seeds

1. Seed Depth:

• Depth: Kohlrabi seeds are small, so only bury them about ¼ inch deep in the soil.
• Spacing: Space seeds about 1 inch apart in each cell.

2. Watering:

• Gently: Water the trays gently using a watering can with a fine rose. Avoid overwatering, as this can lead to root rot.

3. Covering:

• Light: Kohlrabi seeds need light to germinate, so don’t cover them with soil.

4. Labeling:

• Identification: Label each cell with the variety and date of planting for easy tracking.

Providing Optimal Growing Conditions

1. Light:

• Requirement: Kohlrabi seedlings need at least 12-14 hours of light per day.
• Grow Lights: Use fluorescent or LED grow lights positioned about 6-12 inches above the seedlings.
• Sunlight: If you have a sunny windowsill, you can supplement with grow lights to ensure enough light.

2. Temperature:

• Ideal: The ideal temperature for germination and seedling growth is between 65-75 degrees Fahrenheit.
• Heat Mat: Use a heat mat to maintain a consistent temperature, especially if your home is cool.

3. Watering:

• Consistency: Keep the soil consistently moist, but not waterlogged.
• Check for Dryness: Touch the soil surface to check for dryness. Water when the top inch of soil feels dry.

4. Ventilation:

• Airflow: Provide good ventilation to prevent fungal diseases.
• Fan: Use a small fan to circulate air around the seedlings.

Thinning and Transplanting

1. Thinning:

• Purpose: Thin out seedlings once they have two true leaves to give them more space to grow.
• Process: Carefully remove the weakest seedlings, leaving the strongest one in each cell.

2. Hardening Off:

• Preparation: Before transplanting, harden off the seedlings by gradually acclimating them to outdoor conditions.
• Process: Start by placing the seedlings outdoors for a few hours each day, gradually increasing the time until they can handle full sun and wind.

3. Transplanting:

• Timing: Transplant seedlings outdoors after the last frost date, when the soil temperature is at least 60 degrees Fahrenheit.
• Spacing: Space kohlrabi plants 12-18 inches apart in rows that are 18-24 inches apart.
• Watering: Water deeply after transplanting to help the seedlings establish themselves.

Caring for Your Kohlrabi Plants

1. Watering:

• Regularity: Water your kohlrabi plants regularly, especially during dry periods.
• Depth: Water deeply to encourage root growth.

2. Fertilizing:

• Nutrient Needs: Kohlrabi plants are heavy feeders and benefit from regular fertilization.
• Fertilizer Type: Use a balanced fertilizer, such as a 10-10-10 formula, every two weeks.

3. Weeding:

• Competition: Remove weeds regularly to prevent them from competing with your kohlrabi plants for nutrients and water.

4. Pest and Disease Control:

• Monitoring: Monitor your plants regularly for signs of pests or diseases.
• Control: Use organic pest control methods or insecticidal soap to control pests.

Harvesting Your Kohlrabi

1. Timing:

• Size: Harvest kohlrabi when the bulbs are about 2-3 inches in diameter.
• Texture: The bulbs should be firm and crisp to the touch.

2. Harvesting:

• Cut: Use a sharp knife to cut the bulbs just above the soil line.
• Storage: Store harvested kohlrabi in the refrigerator for up to 2 weeks.

The Final Chapter: Enjoy Your Harvest!

With a little patience and care, your indoor-started kohlrabi seeds will reward you with a bountiful harvest of delicious, crunchy bulbs. Enjoy them fresh in salads, stir-fries, or roasted alongside other vegetables. The satisfaction of growing your own food is truly rewarding!

Information You Need to Know

Q: Can I start kohlrabi seeds outdoors?

A: Yes, you can direct sow kohlrabi seeds outdoors after the last frost date. However, starting them indoors gives you an earlier harvest and allows for more control over the growing conditions.

Q: How long does it take for kohlrabi to mature?

A: Kohlrabi typically matures in 60-70 days from planting.

Q: What are some common pests that affect kohlrabi?

A: Common pests include cabbage worms, aphids, and slugs.

Q: Can I grow kohlrabi in containers?

A: Yes, kohlrabi can be grown successfully in containers. Choose a container that is at least 12 inches in diameter and depth.