Kohlrabi is a distinctive and versatile vegetable belonging to the Brassica family, notable for its swollen, bulb-like stem just above ground level. Successful kohlrabi cultivation hinges greatly on proper plant spacing, which influences growth rate, bulb development, and overall yield.
Kohlrabi Plant Spacing Calculator
Estimate how many kohlrabi plants you can grow in your garden bed
You’ll also find at least five detailed tables to help you precisely plan your kohlrabi planting and care!
1. Introduction to Kohlrabi Plant Spacing
Kohlrabi thrives best in cool weather, ideally grown in early spring or fall. Spacing affects how the plants compete for nutrients, water, and sunlight, and how well the swollen stem (often mistaken as a root) develops its characteristic size and tenderness.
Proper spacing improves airflow, which reduces disease incidence, ensures optimal bulb formation, and allows room for mechanical or hand weeding and harvesting.
2. Seed Spacing: Where It All Begins
Kohlrabi seeds are small and often sown directly outdoors or started indoors for transplanting. Seed spacing is:
| Growth Stage | Seed Spacing In-Row | Row Spacing | Notes |
|---|---|---|---|
| Direct sowing seeds | 2 inches (5 cm) apart | 12 inches (30 cm) | Seeds sown densely, then thinned |
| Indoor sowing (seed trays) | Multiple seeds per cell | N/A | Thin seedlings before transplant |
Seeds should be sown about ½ inch (1 cm) deep in rows or containers.
3. Thinning: Refining the Planting Density
Once seedlings develop two or more sets of true leaves, thinning is required to reduce competition and allow space for growth.
| Variety / Purpose | Recommended Spacing After Thinning | Key Tip |
|---|---|---|
| Small early baby kohlrabi | 5 inches (13 cm) apart | Can harvest smaller bulbs |
| Larger main crop kohlrabi | 6 inches (15 cm) apart | Better bulb size and quality |
| Transplanted seedlings | 5-6 inches (13-15 cm) apart | Transplants usually don’t need thinning |
Note: Thinned seedlings can often be carefully transplanted elsewhere for additional harvests.
4. Row Spacing: Organizing the Garden Layout
The distance between rows impacts access, airflow, and sunlight.
| Growing System | Recommended Row Spacing | Comments |
|---|---|---|
| Traditional garden rows | 12 inches (30 cm) | Allows hand weeding and care |
| Raised beds | 12-18 inches (30-45 cm) | Wider rows possible for easier access |
| Commercial-scale row planting | 18-24 inches (45-60 cm) | Allows mechanized cultivation |
5. Table 1: Kohlrabi Spacing Summary
| Growth Stage | In-Row Spacing (in/cm) | Row Spacing (in/cm) | Notes |
|---|---|---|---|
| Seed sowing | 2 in (5 cm) | 12 in (30 cm) | Thin seedlings after germination |
| Seedling thinning | 5-6 in (13-15 cm) | 12-18 in (30-45 cm) | For transplant or direct-seeded crops |
| Transplant planting | 5-6 in (13-15 cm) | 12-18 in (30-45 cm) | Usually no thinning required |
6. Growing Timing and Spacing Considerations
Kohlrabi grows best when temperature ranges stay between 40°F (5°C) and 75°F (24°C). Spacing that is too tight in warmer weather can cause smaller, woody bulbs.
| Season | Planting Timing | Spacing Notes |
|---|---|---|
| Spring | Sow 1-2 weeks before last frost | Standard spacing applies |
| Summer | Avoid planting mid-June to mid-July | Heat may induce bolting, use shade, increase spacing slightly |
| Fall | Plant midsummer to early fall | Cooler temps, standard spacing |
7. Table 2: Kohlrabi Spacing in Raised Beds or Containers
| Container Type | Container Size (gallons/liters) | Number of Plants | Spacing Between Plants (in/cm) |
|---|---|---|---|
| Small pots | 1-2 gallons (4-8 L) | 1 | N/A |
| Medium raised beds | 4-6 gallons (15-23 L) | 2-3 | 5-6 in (13-15 cm) |
| Large raised beds | 10+ gallons (38+ L) | 4-6 | 5-6 in (13-15 cm) |
8. Disease and Pest Prevention Through Spacing
Adequate spacing enhances airflow, reducing humidity and the risk of fungal diseases such as downy mildew and powdery mildew. Dense planting can also encourage pests like cabbage worms.
| Spacing Practice | Disease/Pest Impact |
|---|---|
| Too close >4 in (10 cm) | High risk of diseases and pests |
| Recommended 5-6 in (13-15 cm) spacing | Reduced disease/pest pressure |
| Wider rows with ample spacing (12-18 in) | Easier crop management |
9. Table 3: Kohlrabi Growth Stages and Corresponding Spacing
| Growth Stage | Approximate Size | Spacing Needs | Best Practices |
|---|---|---|---|
| Seedling stage | <2 inches tall | Seeds at 2 in apart | Thin gently to prevent root damage |
| Developing plants | 3-5 inches tall | Thin to 5-6 inches apart | Mulch and water consistently |
| Mature plants | 6+ inches bulb | Maintain 6 inches spacing | Harvest before bulbs get woody |
10. Harvest Timing and Spacing Effects
Kohlrabi is ideally harvested when bulbs are 2-3 inches in diameter. Overcrowding slows growth, producing undersized or tough bulbs.
Spacing allows proper bulb expansion and promotes uniform maturity.
11. Table 4: Typical Yield per Square Foot by Kohlrabi Spacing
| Spacing (inches/cm) | Plants per square foot | Approximate Yield per Plant (grams) | Total Yield per Square Foot (grams) |
|---|---|---|---|
| 2 (5 cm) | 4 | 100 | 400 |
| 5 (13 cm) | 1 | 300 | 300 |
| 6 (15 cm) | 0.75 | 300 | 225 |
12. Environmental Factors Impacting Spacing Decisions
- Heat Stress: In hotter climates, wider spacing reduces competition and stress.
- Soil Fertility: Rich soil can support denser planting.
- Water Availability: Close spacing may increase water demand.
- Microclimate: Shaded or windy areas might affect spacing choices.
13. Table 5: Kohlrabi Spacing Best Practices Recap
| Practice | Recommendation | Notes |
|---|---|---|
| Seed sowing spacing | 2 inches (5 cm) | Thin after emergence |
| Final plant spacing | 5-6 inches (13-15 cm) | For good bulb growth and airflow |
| Row spacing | 12-18 inches (30-45 cm) | Allows access and rooting space |
| Start indoors/transplants | Same spacing as thinning stage | Transplants don’t require thinning |
| Water and mulch | Keep soil moist | Prevents bolting and toughness |
Conclusion
Proper kohlrabi plant spacing is essential for developing crisp, tender bulbs and maximizing yield. Plant seeds about every 2 inches in rows spaced approximately 12 inches apart, then thin seedlings to 5 or 6 inches after they develop true leaves. Transplants follow similar final spacing without thinning. Adjust spacing to suit your climate and soil conditions, balancing plant density with airflow and nutrient availability to minimize disease and ensure healthy growth.
With careful spacing and attentive care, your kohlrabi crop will flourish, rewarding you with a delicious, nutritious harvest enjoyed fresh or cooked.
If you would like assistance with a personalized kohlrabi garden plan or spacing calculator tailored to your specific growing environment, just ask!