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When to Plant Radish in Dona Ana County, NM

Dona Ana County, New Mexico Zone 8b May

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

Welcome to May in Zone 8b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost March 30
Avg. first frost October 30
Soil temp (4") 59°F
Watering Critical
Pest pressure High
Daylight 13.7 hrs
  1. Collect radish at their peak

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

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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.

Dona Ana County, New Mexico is in USDA Zone 8b. The average last spring frost is March 30 and the first fall frost is October 30, giving you a growing season of approximately 214 days.

At an elevation of 4,516 feet, Dona Ana County receives approximately 14.1 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 96°F, so Radish may need afternoon shade and extra watering during peak heat. 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.

Dona Ana County, NM (Zone 8b) Long season
214 days
Last Spring Frost March 30
214 growing days
First Fall Frost October 30

Dona Ana County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.3-8.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (182 days to spare)
Transplant: Mar 5 🍅 Harvest: Apr 2 – Apr 23
Recommended (50%) ✓ Fits season (165 days to spare)
Transplant: Mar 30 🍅 Harvest: Apr 27 – May 18
Safe Start (90%) ✓ Fits season (156 days to spare)
Transplant: May 5 🍅 Harvest: Jun 2 – Jun 23

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 Dona Ana County

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

Soil pH

Your soil pH (7.3–8.9) is more alkaline than Radish prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Dona Ana 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 (0.8%). 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

12
successive plantings in your 214-day season

Sow every 2.4 weeks. Last sowing by Sep 25 to harvest before frost.

For a dedicated fall crop, sow by Aug 21.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.3″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 853 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 0.9" 0" ❄️ Dormant
Mar 2.2" 0.8" 1.4" 🚿 Regular watering
Apr 2.2" 0.4" 1.8" 🚿 Regular watering
May 2.2" 0.3" 1.9" 🚿 Regular watering
Jun 2.2" 0.6" 1.6" 🚿 Regular watering
Jul 2.2" 2.6" 0" ✅ Rainfall sufficient
Aug 2.2" 2.7" 0" ✅ Rainfall sufficient
Sep 2.2" 1.7" 0.5" 💧 Light watering
Oct 2.2" 1.2" 1" 💧 Light watering
Nov 0.8" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Oct in Dona Ana 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 ~627 GDD — county provides 4,708 GDD Excellent fit

Radish Planting Timeline — Dona Ana County, NM

Radish Planting Calendar

Activity When Date Range
Direct Sow March 16 Mar 16 – Apr 6
Harvest April 13 Apr 13 – May 4
Fall Sowing August 21 Aug 21 – Sep 4

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · 1-2 times/week

📅 Days to Maturity

22–35 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 8b

📆 Growing Season

214 days in Dona Ana County

Growing Tips for Radish in Dona Ana County

Direct sow Radish outdoors after March 30 in Dona Ana County when soil has warmed and frost danger has passed.

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

Summer highs in Dona Ana County reach 96°F — grow Radish as a spring or fall crop. Use shade cloth if planting in summer.

Your generous 214.0-day season in Dona Ana 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 Dona Ana County, NM?

Dona Ana County is in Zone 8b with an average last frost of March 30. Plan your Radish planting based on this frost date — see the calendar above for exact timing.

What planting zone is Dona Ana County, NM?

Dona Ana County, New Mexico is in USDA Hardiness Zone 8b. The average last spring frost is March 30 and first fall frost is October 30.

🌱

Your Dona Ana County Garden Planner — Free

A 24-page printable planner built for Dona Ana County (Zone 8b). 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 Dona Ana 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.