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When to Plant Radish in Colfax County, NM

Colfax County, New Mexico Zone 6a May

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

A quick May briefing for Colfax County, New Mexico gardeners — what's urgent, what's next, and what can wait.

Avg. last frost May 15
Avg. first frost September 26
Soil temp (4") 47°F
Watering Critical
Pest pressure Low
Daylight 14 hrs
  1. Direct-sow radish

    Sow every 2 weeks for a continuous harvest. A single big planting means a single big glut.

  2. Harvest radish as they ripen

    If you can't use it all right away, check the food-preservation section of your planner.

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

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Radishes are one of the fastest-growing vegetables, with some varieties ready in under a month. They come in round, elongated, and large winter types.

Colfax County, New Mexico is in USDA Zone 6a. The average last spring frost is May 15 and the first fall frost is September 26, giving you a growing season of approximately 134 days.

At an elevation of 5,131 feet, Colfax County receives approximately 15.5 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 84°F, so choose short-season varieties of Radish to ensure they mature before fall. Sandy soil warms quickly in spring — great for early planting — but Radish will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Radish successfully. Mulch heavily to conserve soil moisture.

Colfax County, NM (Zone 6a) Short season
134 days
Last Spring Frost May 15
134 growing days
First Fall Frost September 26
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Colfax County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.1-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (85 days to spare)
Transplant: May 6 🍅 Harvest: Jun 3 – Jun 24
Recommended (50%) ✓ Fits season (85 days to spare)
Transplant: May 15 🍅 Harvest: Jun 12 – Jul 3
Safe Start (90%) ✓ Fits season (69 days to spare)
Transplant: Jun 16 🍅 Harvest: Jul 14 – Aug 4

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 Colfax County

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

Soil pH

Your soil pH (7.1–8.1) is more alkaline than Radish prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Colfax County warms quickly in spring but drains fast. Radish will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Radish.

Organic Matter

Organic matter is low (0.9%). Add 2-3 inches of compost before planting Radish.

How to Plant Radish

0.5"
Planting Depth
2"
Between Plants
6"
Between Rows

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

Succession Planting Radish

7
successive plantings in your 134-day season

Sow every 2.4 weeks. Last sowing by Aug 22 to harvest before frost.

For a dedicated fall crop, sow by Jul 18.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.5″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 235 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Radish

Radish needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Radish Needs Rainfall You Supplement Action
Jan 1.1" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 0.9" 0" ❄️ Dormant
Apr 0.5" 0" ❄️ Dormant
May 2.2" 0.4" 1.8" 🚿 Regular watering
Jun 2.2" 0.5" 1.7" 🚿 Regular watering
Jul 2.2" 3" 0" ✅ Rainfall sufficient
Aug 2.2" 2.9" 0" ✅ Rainfall sufficient
Sep 2.2" 2" 0.2" 💧 Light watering
Oct 1.3" 0" ❄️ Dormant
Nov 1" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Colfax County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Radish 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.

Radish needs ~370 GDD — county provides 1,742 GDD Excellent fit

Radish Planting Timeline — Colfax County, NM

Radish Planting Calendar

Activity When Date Range
Direct Sow May 1 May 1 – May 22
Harvest May 29 May 29 – Jun 19
Fall Sowing July 18 Jul 18 – Aug 1

Plant 0.5" deep · 2" apart · Rows 6" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Direct Sow Harvest
June Harvest
July Fall Sowing
August Fall Sowing
September
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Only during dry spells

📅 Days to Maturity

22–35 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6a

📆 Growing Season

134 days in Colfax County

Growing Tips for Radish in Colfax County

Direct sow Radish outdoors after May 15 in Colfax County when soil has warmed and frost danger has passed.

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

Your generous 134.0-day season in Colfax County allows multiple plantings of Radish. Sow every 11.0 days for continuous harvest.

Common pests for Radish 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 every 1-2 weeks for continuous harvest. Do not transplant. Harvest spring radishes promptly to prevent them from becoming pithy and hot.

Companion Planting

Good Companions

Avoid Planting Near

  • Hyssop

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Radish in Colfax County, NM?

Colfax County is in Zone 6a with an average last frost of May 15. Plan your Radish planting based on this frost date — see the calendar above for exact timing.

What planting zone is Colfax County, NM?

Colfax County, New Mexico is in USDA Hardiness Zone 6a. The average last spring frost is May 15 and first fall frost is September 26.

🌱

Your Colfax County Garden Planner — Free

A 24-page printable planner built for Colfax 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.

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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 Colfax 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.