When to Plant Kohlrabi in Douglas County, OR
What to do in May
Your garden in Douglas County, Oregon is working on a schedule, even when you're not. Here's where you should be this May.
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Sow kohlrabi in trays indoors
Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.
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Harvest kohlrabi as they ripen
Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.
June prep starts now
- First harvests: kohlrabi
Kohlrabi is an unusual brassica that forms a swollen stem above ground with a mild, sweet turnip-like flavor. Both the bulb and tender leaves are edible.
Douglas County, Oregon is in USDA Zone 8b. The average last spring frost is April 4 and the first fall frost is November 5, giving you a growing season of approximately 215 days.
At an elevation of 377 feet, Douglas County receives approximately 52.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Kohlrabi during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Kohlrabi root diseases.
Douglas County Soil Profile
Soil Type
Silt Loam
Soil pH
5.8-6.4
Drainage
Well Drained
Plant Planting Risk Windows
Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.
Soil Compatibility in Douglas County
How your county's soil matches Kohlrabi's growing requirements.
Soil pH
Your soil pH (5.8–6.4) overlaps with Kohlrabi's range (6.0–7.5), though not a perfect match.
Soil Texture
The silt loam soil in Douglas County is excellent for Kohlrabi — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.4%) — Kohlrabi will thrive.
How to Plant Kohlrabi
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Kohlrabi
Sow every 5.1 weeks. Last sowing by Sep 01 to harvest before frost.
For a dedicated fall crop, sow by Aug 27.
Plant Water Budget
Monthly Watering Guide for Kohlrabi
Kohlrabi needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.
| Month | Kohlrabi Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 8.6" | 0" | ❄️ Dormant |
| Feb | — | 6.2" | 0" | ❄️ Dormant |
| Mar | — | 4.9" | 0" | ❄️ Dormant |
| Apr | 3" | 4.3" | 0" | ✅ Rainfall sufficient |
| May | 3" | 3.4" | 0" | ✅ Rainfall sufficient |
| Jun | 3" | 2.3" | 0.7" | 💧 Light watering |
| Jul | 3" | 0.8" | 2.2" | 🚿 Regular watering |
| Aug | 3" | 1" | 2" | 🚿 Regular watering |
| Sep | 3" | 2.2" | 0.8" | 💧 Light watering |
| Oct | 3" | 4" | 0" | ✅ Rainfall sufficient |
| Nov | 3" | 7.6" | 0" | ✅ Rainfall sufficient |
| Dec | — | 7.4" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Nov in Douglas County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Kohlrabi Heat Requirements (GDD)
What are Growing Degree Days (GDD)?
Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.
Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.
Kohlrabi Planting Timeline — Douglas County, OR
Kohlrabi Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 28 | Feb 28 – Mar 14 |
| Transplant Outdoors | April 4 | Apr 4 – Apr 18 |
| Direct Sow | March 21 | Mar 21 – Apr 11 |
| Harvest | May 23 | May 23 – Jun 27 |
| Fall Sowing | August 27 | Aug 27 – Sep 10 |
Plant 0.5" deep · 4" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | Harvest |
| June | Harvest |
| July | — |
| August | Fall Sowing |
| September | Fall Sowing |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.7"/week · Natural rainfall sufficient
📅 Days to Maturity
45–65 days
🧪 Soil pH
Needs 6–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 8b
📆 Growing Season
215 days in Douglas County
Growing Tips for Kohlrabi in Douglas County
Direct sow Kohlrabi outdoors after April 04 in Douglas County when soil has warmed and frost danger has passed.
Your generous 215.0-day season in Douglas County allows multiple plantings of Kohlrabi. Sow every 22.0 days for continuous harvest.
Common pests for Kohlrabi in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
Direct sow in spring or fall. Harvest when bulbs are 2-3 inches in diameter for best texture and flavor. Larger bulbs may become woody and fibrous.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Kohlrabi in Other Locations
Frequently Asked Questions
When should I plant Kohlrabi in Douglas County, OR?
Douglas County is in Zone 8b with an average last frost of April 4. Plan your Kohlrabi planting based on this frost date — see the calendar above for exact timing.
What planting zone is Douglas County, OR?
Douglas County, Oregon is in USDA Hardiness Zone 8b. The average last spring frost is April 4 and first fall frost is November 5.
Your Douglas County Garden Planner — Free
A 24-page printable planner built for Douglas County (Zone 8b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.