When to Plant Kohlrabi in Union County, NM
Your May game plan for Union County, New Mexico
Welcome to May in Zone 6b. These are the moves that will have the biggest impact on your growing season.
Looking ahead to 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.
Union County, New Mexico is in USDA Zone 6b. The average last spring frost is April 30 and the first fall frost is October 9, giving you a growing season of approximately 162 days.
At an elevation of 6,384 feet, Union County receives approximately 17.5 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 85°F, providing good warmth for Kohlrabi during the growing season. Sandy soil warms quickly in spring — great for early planting — but Kohlrabi will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Kohlrabi successfully. Mulch heavily to conserve soil moisture.
Union County Soil Profile
Soil Type
Sandy Loam
Soil pH
6.9-8.3
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 Union County
How your county's soil matches Kohlrabi's growing requirements.
Soil pH
Your soil pH (6.9–8.3) is more alkaline than Kohlrabi prefers (6.0–7.5). Add sulfur or peat moss to lower pH.
Soil Texture
Sandy soil in Union County warms quickly in spring but drains fast. Kohlrabi will need more frequent watering and regular compost additions to retain nutrients.
Drainage
Drainage is adequate for Kohlrabi.
Organic Matter
Organic matter is low (0.9%). Add 2-3 inches of compost before planting 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 Aug 05 to harvest before frost.
For a dedicated fall crop, sow by Jul 31.
Plant Water Budget
Water stress score is 10/10 — 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 | — | 1.1" | 0" | ❄️ Dormant |
| Feb | — | 0.9" | 0" | ❄️ Dormant |
| Mar | — | 1" | 0" | ❄️ Dormant |
| Apr | 3" | 0.6" | 2.4" | 🚿 Regular watering |
| May | 3" | 0.4" | 2.6" | 🚿 Regular watering |
| Jun | 3" | 0.6" | 2.4" | 🚿 Regular watering |
| Jul | 3" | 3" | 0" | ✅ Rainfall sufficient |
| Aug | 3" | 4" | 0" | ✅ Rainfall sufficient |
| Sep | 3" | 2.1" | 0.9" | 💧 Light watering |
| Oct | 3" | 1.4" | 1.6" | 🚿 Regular watering |
| Nov | — | 1" | 0" | ❄️ Dormant |
| Dec | — | 1.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Union 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 — Union County, NM
Kohlrabi Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 26 | Mar 26 – Apr 9 |
| Transplant Outdoors | April 30 | Apr 30 – May 14 |
| Direct Sow | April 16 | Apr 16 – May 7 |
| Harvest | June 18 | Jun 18 – Jul 23 |
| Fall Sowing | July 31 | Jul 31 – Aug 14 |
Plant 0.5" deep · 4" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors Transplant Outdoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | Harvest |
| July | Fall Sowing Harvest |
| August | Fall Sowing |
| 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: too_alkaline
🗺️ USDA Zone
Zone 6b
📆 Growing Season
162 days in Union County
Growing Tips for Kohlrabi in Union County
Direct sow Kohlrabi outdoors after April 30 in Union County when soil has warmed and frost danger has passed.
Sandy soil in Union County dries quickly — mulch Kohlrabi with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.
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
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Check more plant combinations with our Companion Planting Checker →
Kohlrabi in Other Locations
Frequently Asked Questions
When should I plant Kohlrabi in Union County, NM?
Union County is in Zone 6b with an average last frost of April 30. Plan your Kohlrabi planting based on this frost date — see the calendar above for exact timing.
What planting zone is Union County, NM?
Union County, New Mexico is in USDA Hardiness Zone 6b. The average last spring frost is April 30 and first fall frost is October 9.
Your Union County Garden Planner — Free
A 24-page printable planner built for Union County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.