Kohlrabi, often called the “German turnip,” is a unique and versatile vegetable known for its crisp texture, mild flavor, and high nutritional value. Rich in vitamin C, potassium, fiber, and antioxidants, kohlrabi can be eaten raw in salads, roasted, sautéed, or added to soups and stews. Traditionally grown in garden beds, kohlrabi can also thrive in unconventional spaces—like a simple plastic bottle.
In this blog, we reveal the secret behind growing kohlrabi in a plastic bottle. This method is perfect for urban gardeners, small-space growers, and anyone looking to combine sustainability with home gardening. Using just a few recycled bottles, you can cultivate healthy, productive kohlrabi plants without the need for a traditional garden bed.
Why Grow Kohlrabi in a Plastic Bottle?
- Space-Efficient: Perfect for balconies, windowsills, or small patios.
- Eco-Friendly: Reuses plastic bottles, reducing household waste.
- Controlled Growth: Container growing allows for easy soil and water management.
- Pest Management: Elevated bottles reduce the risk of soil-borne pests.
- Fun and Educational: Great for beginners, children, or anyone experimenting with creative gardening methods.
Materials You’ll Need
- Plastic bottles (1–2 liters recommended)
- Utility knife or scissors
- Potting soil or garden soil mixed with compost
- Kohlrabi seeds or seedlings
- Cotton string or cloth (optional for self-watering)
- Small pebbles (optional for drainage)
- Water
- Fertilizer (organic or balanced liquid fertilizer)
Step 1: Preparing the Plastic Bottle
- Wash the bottle thoroughly to remove any residue.
- Cut the bottle horizontally about one-third from the top, creating a top section for soil and a bottom section for water if you want a self-watering system.
- Make small drainage holes at the bottom of the top section to prevent waterlogging.
- Optional: Thread a cotton string through the bottle neck to act as a wick, drawing water from the bottom reservoir to the soil.
Step 2: Adding Soil and Drainage
- Optional: Place a layer of small pebbles at the bottom for drainage.
- Fill the top part with nutrient-rich soil or a mix of compost and garden soil. Kohlrabi prefers fertile, well-draining soil with a pH between 6.0–7.5.
- Leave about an inch from the top for watering and planting seeds or seedlings.
- Ensure the cotton wick or soil contacts the water if using a self-watering system.
Step 3: Planting Kohlrabi Seeds or Seedlings
- From Seeds: Sprinkle 2–3 kohlrabi seeds on the soil surface, covering lightly with soil.
- From Seedlings: Dig a small hole and plant the seedlings, ensuring the root is well-covered but the leaves remain above the soil.
- Water gently to settle the soil and encourage germination.
Step 4: Setting Up a Self-Watering System (Optional)
- Fill the bottom reservoir with water.
- Ensure the wick or soil touches the water, allowing gradual moisture absorption.
- Check water levels periodically and refill as needed to keep the soil consistently moist.
Step 5: Caring for Kohlrabi in Plastic Bottles
- Sunlight: Place bottles in a location receiving at least 4–6 hours of sunlight daily. Kohlrabi grows best in full sun but tolerates partial shade.
- Watering: Keep soil evenly moist. Consistent moisture is crucial to prevent tough or woody bulbs.
- Fertilizing: Apply a balanced liquid fertilizer every 2–3 weeks to encourage healthy bulb growth.
- Pruning: Remove yellowing or damaged leaves to improve airflow and reduce disease risk.
- Pest Management: Watch for aphids, flea beetles, or cabbage worms. Use neem oil or mild soap sprays for organic control.
Tips for Maximizing Growth
- Thin Seedlings: If multiple seeds germinate in one bottle, thin to the strongest plant to prevent overcrowding.
- Use Tall Bottles: Kohlrabi develops bulbs that need space; deeper bottles provide enough room for roots.
- Temperature: Kohlrabi prefers cooler temperatures (60–75°F). Provide shade during hot spells if necessary.
- Rotate Bottles: Rotate bottles occasionally to ensure even sunlight exposure.
- Harvest Regularly: Pick mature bulbs promptly to encourage continuous growth.
Harvesting Kohlrabi
- Kohlrabi bulbs are typically ready for harvest 50–70 days after planting.
- Harvest when the bulbs reach 2–3 inches in diameter for optimal tenderness.
- Cut the bulb from the base, leaving roots in the soil to potentially produce secondary growth.
- Younger leaves can also be harvested as greens for salads and cooking.
Common Challenges and Solutions
- Forked or Deformed Bulbs: Often caused by overcrowding or compacted soil. Ensure proper spacing and loose soil.
- Slow Growth: Can occur in hot temperatures or poor soil. Keep soil fertile, moist, and in a cooler spot if possible.
- Pests: Aphids and cabbage worms can damage leaves and bulbs. Inspect plants regularly and treat organically.
- Overwatering: Leads to root rot. Make sure drainage holes are clear, and water moderately.
- Bolt (Premature Flowering): Occurs if plants are stressed by heat. Maintain consistent moisture and temperature.
Benefits of Growing Kohlrabi in Plastic Bottles
- Fresh, Nutritious Produce: Homegrown kohlrabi is crisp, flavorful, and rich in nutrients.
- Eco-Friendly Gardening: Recycles plastic bottles and reduces household waste.
- Space-Saving: Ideal for urban gardens or small spaces.
- Low Maintenance: Self-watering bottles reduce daily watering effort.
- Continuous Yield: Regular harvesting and proper care ensure a steady supply of kohlrabi bulbs and greens.
Tips for Year-Round Kohlrabi Gardening
- Indoor Growing: Use grow lights or place bottles near sunny windows for winter or cold-season growing.
- Succession Planting: Plant seeds every few weeks for continuous harvest.
- Companion Plants: Grow kohlrabi alongside herbs or smaller leafy greens to maximize container space.
- Experiment with Varieties: Try different kohlrabi varieties for color, size, and flavor differences.
Expanding Your Plastic Bottle Garden
Once you’ve mastered growing kohlrabi, other vegetables can thrive in similar setups:
- Radishes and turnips
- Lettuce and spinach
- Green onions and herbs
- Small root vegetables like carrots and beets
This method allows urban gardeners to maximize productivity in limited spaces while recycling plastic responsibly.
Conclusion
The secret behind growing kohlrabi in a plastic bottle lies in understanding the plant’s needs and creatively adapting container gardening techniques. With proper soil, consistent watering, sunlight, and care, you can cultivate healthy kohlrabi bulbs in a small, space-saving setup.
This method is perfect for urban gardeners, beginners, or anyone interested in sustainable and low-maintenance gardening. By following the steps outlined—from preparing the bottle and planting seeds to regular care and harvesting—you can enjoy fresh, nutritious kohlrabi at home all year round.
Start your plastic bottle kohlrabi garden today and discover the simplicity and satisfaction of growing your own vegetables, even in the smallest of spaces.