Zone 9 · Brassicas Growing Guide

When to Plant Kohlrabi
in Zone 9

The alien-looking brassica that deserves far more attention. Crisp, mild, sweet flavour — eat raw like an apple or cooked. Very fast-maturing and easier than broccoli or cabbage.

Plant outdoors
Sep – Mar
Start indoors
Direct sow
Last Frost
~Jan 31
Days to harvest
45–60 days
Difficulty
Easy
Ready to harvest — Zone 9
Harvest window: Oct – May

Planting Calendar

In Zone 9, Kohlrabi should be planted outdoors Sep – Mar, after the average last frost date of approximately Jan 31.

Fall through spring. Direct sow September.

Care Guide

Sunlight
Full sun · 6–8 hrs/day
Watering
Regular
Spacing
5–7 inches
Soil
Fertile, well-draining
Days to maturity
45–60 days
Soil pH
6.0–7.5
plant tip · Zone 9

Fall through spring. Direct sow September.

Feeding Schedule

How often
every 3 weeks
Feed type
balanced (10-10-10)
Key timing
throughout growing season

Moderate feeder. Consistent balanced feeding produces well-formed bulbs. Avoid excess nitrogen.

Succession Planting

Sow every 3 weeks

Sow every 3 weeks from early spring through early summer, then again in late summer. Gets woody if left too long — succession keeps you harvesting at the right size.

Companion Planting for Kohlrabi

What you plant next to kohlrabi makes a real difference — some plants actively help, others compete or attract pests.

Grows well with
  • Beets
  • Onions
  • Cucumbers
Keep away from
  • Tomatoes
  • Strawberries
  • Pole beans

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Common questions

In Zone 9, kohlrabi is a fall-planted crop. Plant outdoors Sep – Mar once temperatures cool in autumn. It overwinters and is ready to harvest around Oct – May. No last frost consideration — plant before the ground freezes.
Zone 9 has an average last spring frost of approximately Jan 31 and a first fall frost around Dec 15. These dates vary by specific location — use your ZIP code in the plant app for precision based on the nearest NOAA weather station.
Good companion crops for kohlrabi include Beets, Onions, Cucumbers. Avoid planting near Tomatoes, Strawberries, Pole beans, which can compete for nutrients or attract pests.
Kohlrabi typically takes 45–60 days from transplant or direct sow to harvest in Zone 9. Expected harvest window: Oct – May.

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Kohlrabi in other zones
Crop Guides