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When to Plant Kohlrabi in Sierra County, NM

Sierra County, New Mexico Zone 8a May

Sierra County, New Mexico gardeners: here's your May plan

We've pulled the most time-sensitive tasks for Sierra County, New Mexico this May and put them front and centre. Tackle them in order.

Avg. last frost April 15
Avg. first frost October 26
Soil temp (4") 55°F
Watering Critical
Pest pressure Moderate
Daylight 13.7 hrs
  1. Begin indoor sowing: kohlrabi

    These need a head start before your last frost (April 15). Sow into cells now so you're ready to transplant in a few weeks.

Coming up in June — start thinking about
  • First harvests: kohlrabi

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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.

Sierra County, New Mexico is in USDA Zone 8a. The average last spring frost is April 15 and the first fall frost is October 26, giving you a growing season of approximately 194 days.

At an elevation of 4,898 feet, Sierra County receives approximately 17.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 88°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.

Sierra County, NM (Zone 8a) Moderate season
194 days
Last Spring Frost April 15
194 growing days
First Fall Frost October 26
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Sierra County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.3-8.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (121 days to spare)
Start indoors: Feb 23 Transplant: Mar 30 🍅 Harvest: May 18 – Jun 22
Recommended (50%) ✓ Fits season (110 days to spare)
Start indoors: Mar 11 Transplant: Apr 15 🍅 Harvest: Jun 3 – Jul 8
Safe Start (90%) ✓ Fits season (115 days to spare)
Start indoors: Mar 30 Transplant: May 4 🍅 Harvest: Jun 22 – Jul 27

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 Sierra County

How your county's soil matches Kohlrabi's growing requirements.

Soil pH

Your soil pH (7.3–8.5) is more alkaline than Kohlrabi prefers (6.0–7.5). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Sierra 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 (0.7%). Add 2-3 inches of compost before planting Kohlrabi.

How to Plant Kohlrabi

0.5"
Planting Depth
4"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Kohlrabi

5
successive plantings in your 194-day season

Sow every 5.1 weeks. Last sowing by Aug 22 to harvest before frost.

For a dedicated fall crop, sow by Aug 17.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.4″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 1,105 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 1.4" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1" 0" ❄️ Dormant
Apr 3" 0.6" 2.4" 🚿 Regular watering
May 3" 0.4" 2.6" 🚿 Regular watering
Jun 3" 0.5" 2.5" 🚿 Regular watering
Jul 3" 2.7" 0.3" 💧 Light watering
Aug 3" 3.3" 0" ✅ Rainfall sufficient
Sep 3" 2.3" 0.7" 💧 Light watering
Oct 3" 1.7" 1.3" 💧 Light watering
Nov 1" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Sierra 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 needs ~880 GDD — county provides 3,104 GDD Excellent fit

Kohlrabi Planting Timeline — Sierra County, NM

Kohlrabi Planting Calendar

Activity When Date Range
Start Indoors March 11 Mar 11 – Mar 25
Transplant Outdoors April 15 Apr 15 – Apr 29
Direct Sow April 1 Apr 1 – Apr 22
Harvest June 3 Jun 3 – Jul 8
Fall Sowing August 17 Aug 17 – Aug 31

Plant 0.5" deep · 4" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Transplant Outdoors Direct Sow
May
June Harvest
July Harvest
August Fall Sowing
September
October
November
December
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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 8a

📆 Growing Season

194 days in Sierra County

Growing Tips for Kohlrabi in Sierra County

Direct sow Kohlrabi outdoors after April 15 in Sierra County when soil has warmed and frost danger has passed.

Sandy soil in Sierra County dries quickly — mulch Kohlrabi with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

Your generous 194.0-day season in Sierra 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

  • Tomatoes
  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Kohlrabi in Sierra County, NM?

Sierra County is in Zone 8a with an average last frost of April 15. Plan your Kohlrabi planting based on this frost date — see the calendar above for exact timing.

What planting zone is Sierra County, NM?

Sierra County, New Mexico is in USDA Hardiness Zone 8a. The average last spring frost is April 15 and first fall frost is October 26.

🌱

Your Sierra County Garden Planner — Free

A 24-page printable planner built for Sierra County (Zone 8a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Sierra County, NM. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.