When to Plant Kohlrabi in Grand Forks County, ND
Your May game plan for Grand Forks County, North Dakota
If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.
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Time to transplant kohlrabi
Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.
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Seed kohlrabi outdoors
Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.
Get ahead of June
- Starting indoors: kohlrabi
- 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.
Grand Forks County, North Dakota is in USDA Zone 4a. The average last spring frost is May 11 and the first fall frost is September 30, giving you a growing season of approximately 142 days.
At an elevation of 572 feet, Grand Forks County receives approximately 27.7 inches of rainfall annually with predominantly loam soil. Summer highs average 79°F, so choose short-season varieties of Kohlrabi to ensure they mature before fall.
Grand Forks County Soil Profile
Soil Type
Loam
Soil pH
6.8-7.4
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 Grand Forks County
How your county's soil matches Kohlrabi's growing requirements.
Soil pH
Your soil pH (6.8–7.4) is within Kohlrabi's preferred range (6.0–7.5).
Soil Texture
The loam soil in Grand Forks County is excellent for Kohlrabi — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.3%). Annual compost additions will help Kohlrabi.
How to Plant Kohlrabi
Fall planting: Sow 12 weeks before your first frost date for a fall harvest.
Succession Planting Kohlrabi
Sow every 5.1 weeks. Last sowing by Jul 27 to harvest before frost.
For a dedicated fall crop, sow by Jul 08.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
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 | — | 0.8" | 0" | ❄️ Dormant |
| Feb | — | 1" | 0" | ❄️ Dormant |
| Mar | — | 1.9" | 0" | ❄️ Dormant |
| Apr | — | 3.2" | 0" | ❄️ Dormant |
| May | 3" | 4.1" | 0" | ✅ Rainfall sufficient |
| Jun | 3" | 4.6" | 0" | ✅ Rainfall sufficient |
| Jul | 3" | 3" | 0" | ✅ Rainfall sufficient |
| Aug | 3" | 3.6" | 0" | ✅ Rainfall sufficient |
| Sep | 3" | 2.5" | 0.5" | 💧 Light watering |
| Oct | — | 1.8" | 0" | ❄️ Dormant |
| Nov | — | 0.8" | 0" | ❄️ Dormant |
| Dec | — | 0.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Grand Forks 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 — Grand Forks County, ND
Kohlrabi Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 30 | Mar 30 – Apr 13 |
| Transplant Outdoors | May 11 | May 11 – May 25 |
| Direct Sow | May 4 | May 4 – May 25 |
| Harvest | June 29 | Jun 29 – Aug 3 |
| Fall Sowing | July 8 | Jul 8 – Jul 22 |
Plant 0.5" deep · 4" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | Harvest |
| July | Fall Sowing Harvest |
| August | Harvest |
| September | — |
| 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: ideal
🗺️ USDA Zone
Zone 4a
📆 Growing Season
142 days in Grand Forks County
Growing Tips for Kohlrabi in Grand Forks County
Direct sow Kohlrabi outdoors after May 11 in Grand Forks County when soil has warmed and frost danger has passed.
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 Grand Forks County, ND?
Grand Forks County is in Zone 4a with an average last frost of May 11. Plan your Kohlrabi planting based on this frost date — see the calendar above for exact timing.
What planting zone is Grand Forks County, ND?
Grand Forks County, North Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 11 and first fall frost is September 30.
Your Grand Forks County Garden Planner — Free
A 24-page printable planner built for Grand Forks County (Zone 4a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.