Kohlrabi
Brassica oleracea var. gongylodes
family
Brassicaceae
Difficulty factors: Forgiving of beginner mistakes, Short time to harvest
duration
Biennial
growth habit
Forb
why learn this plant?
Kohlrabi teaches fundamental vegetable growing skills including soil preparation, watering consistency, and harvest timing.
timeline
germination
7-14
days to maturity
45-60
growth stages
Germination/Establishment
1-2 weeks
Seeds swell and sprout, or transplants establish roots
Check in:
Look for first signs of green growth emerging from soil
Tasks:
- Keep soil consistently moist
- Maintain temperature
- Protect from strong wind
Watch for:
- Damping off from overwatering
- Poor germination from old seed
Seedling
2-4 weeks
True leaves develop, stem strengthens
Check in:
Count true leaves — ready for transplant at 2-4 sets
Tasks:
- Thin seedlings if direct-sown
- Begin light fertilizing
- Harden off if started indoors
Watch for:
- Leggy seedlings from insufficient light
- Transplant shock
Vegetative Growth
3-8 weeks
Rapid leaf and stem growth, plant fills out
Check in:
Plant should be growing visibly each week
Tasks:
- Regular watering
- Fertilize on schedule
- Add support if needed
- Watch for pests
Watch for:
- Nutrient deficiency (yellowing leaves)
- Pest damage
Flowering/Fruiting
2-6 weeks
Flowers appear, followed by fruit development
Check in:
Note first flower date — track pollination success
Tasks:
- Ensure pollination
- Continue consistent watering
- Side-dress with fertilizer
Watch for:
- Blossom drop from heat stress
- Poor pollination
Harvest
2-8 weeks
Fruits ripen, ready for picking
Check in:
Check daily at peak — many crops taste best picked slightly early
Tasks:
- Harvest regularly to encourage production
- Record yield
- Watch for overripe fruit
Watch for:
- Splitting from irregular watering
- Pest damage to ripe fruit
how to grow
starting method
either
sun requirements
Full sun/partial shade
spacing
6-8 inches" × "6-8 inches"
planting depth
1/4 inch
water needs
Frequency: Every 2-3 days
Amount: 1 inch per week
Method: Drip irrigation or soaker hose preferred. Water at base, avoid wetting leaves.
soil & fertilizer
Amend with compost. Preferred pH: 6.0-7.5. Soil type: Well-drained, fertile soil.
At planting: Balanced 10-10-10 or compost
During growth: Balanced fertilizer every 3-4 weeks every Every 2-4 weeks during growing season
zone timing guide
Best grown when temperatures are 60-80°F. Plant after last frost in spring.
Zone 3
Start indoors: April
Transplant: Late May-June
Short growing season, choose early varieties
Zone 4-5
Start indoors: March-April
Transplant: May-June
Direct sow: May
Zone 6-7
Start indoors: February-March
Transplant: April-May
Direct sow: April-May
Zone 8-9
Start indoors: January-February
Transplant: March-April
Direct sow: March
Zone 10+
Direct sow: February-March
Year-round growing possible
harvest guide
Visual cue
Mature size reached, typical color for variety. Harvest when kohlrabi looks ready.
Feel
Firm but not hard. Should separate from plant easily.
Timing
Typically 45-60 days from planting
Storage
Store in cool location. Use within 1-2 weeks for best quality.
what can go wrong
Overwatering
Visual cue:
Yellowing lower leaves, mushy stems, mold on soil surface
Why it happens:
Too frequent watering without checking soil moisture
Prevention:
Check soil moisture before watering — stick finger 1 inch into soil
If it happens:
Allow soil to dry out between waterings. Improve drainage.
Insufficient light
Visual cue:
Leggy, stretched growth with pale leaves
Why it happens:
Planted in too much shade or crowded by other plants
Prevention:
Ensure at least 6-8 hours of direct sunlight
If it happens:
Transplant to sunnier location or thin surrounding plants
Cabbage worms
Visual cue:
Holes in leaves, green caterpillars on leaf undersides
Why it happens:
White butterflies laying eggs on plants
Prevention:
Cover with floating row cover
If it happens:
Hand-pick caterpillars, apply BT (Bacillus thuringiensis)
skill progression
related plants
ready to grow Kohlrabi?
Join the waitlist for personalized growing guides, location-based timing, and community support.