When to Plant Kohlrabi in Broomfield County, CO
This month in Broomfield County, Colorado
May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Broomfield County, Colorado.
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Time to transplant kohlrabi
Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.
A few tasks this May that'll pay off in June
- Starting indoors: 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.
Broomfield County, Colorado is in USDA Zone 6a. The average last spring frost is May 14 and the first fall frost is September 26, giving you a growing season of approximately 135 days.
At an elevation of 7,037 feet, Broomfield County receives approximately 13.9 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Kohlrabi during the growing season. With low rainfall, drip irrigation is essential for growing Kohlrabi successfully. Mulch heavily to conserve soil moisture.
Broomfield County Soil Profile
Soil Type
Loam
Soil pH
6.2-8.2
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 Broomfield County
How your county's soil matches Kohlrabi's growing requirements.
Soil pH
Your soil pH (6.2–8.2) overlaps with Kohlrabi's range (6.0–7.5), though not a perfect match.
Soil Texture
The loam soil in Broomfield County is excellent for Kohlrabi — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.9%). Annual compost additions will help Kohlrabi.
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 Jul 23 to harvest before frost.
For a dedicated fall crop, sow by Jul 18.
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 | — | 0.9" | 0" | ❄️ Dormant |
| Feb | — | 0.7" | 0" | ❄️ Dormant |
| Mar | — | 1.1" | 0" | ❄️ Dormant |
| Apr | — | 1.5" | 0" | ❄️ Dormant |
| May | 3" | 1.7" | 1.3" | 💧 Light watering |
| Jun | 3" | 0.9" | 2.1" | 🚿 Regular watering |
| Jul | 3" | 1.3" | 1.7" | 🚿 Regular watering |
| Aug | 3" | 1.6" | 1.4" | 💧 Light watering |
| Sep | 3" | 1.1" | 1.9" | 🚿 Regular watering |
| Oct | — | 1.2" | 0" | ❄️ Dormant |
| Nov | — | 1" | 0" | ❄️ Dormant |
| Dec | — | 0.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Broomfield 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 — Broomfield County, CO
Kohlrabi Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 9 | Apr 9 – Apr 23 |
| Transplant Outdoors | May 14 | May 14 – May 28 |
| Direct Sow | April 30 | Apr 30 – May 21 |
| Harvest | July 2 | Jul 2 – Aug 6 |
| Fall Sowing | July 18 | Jul 18 – Aug 1 |
Plant 0.5" deep · 4" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Fall Sowing Harvest |
| August | Fall Sowing Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.7"/week · 1-2 times/week
📅 Days to Maturity
45–65 days
🧪 Soil pH
Needs 6–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 6a
📆 Growing Season
135 days in Broomfield County
Growing Tips for Kohlrabi in Broomfield County
Direct sow Kohlrabi outdoors after May 14 in Broomfield 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 Broomfield County, CO?
Broomfield County is in Zone 6a with an average last frost of May 14. Plan your Kohlrabi planting based on this frost date — see the calendar above for exact timing.
What planting zone is Broomfield County, CO?
Broomfield County, Colorado is in USDA Hardiness Zone 6a. The average last spring frost is May 14 and first fall frost is September 26.
Your Broomfield County Garden Planner — Free
A 24-page printable planner built for Broomfield County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.