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When to Plant Radish in Conejos County, CO

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.

Conejos County, Colorado is in USDA Zone 4b. The average last spring frost is June 9 and the first fall frost is September 17, giving you a growing season of approximately 100 days.

At an elevation of 6,770 feet, Conejos County receives approximately 24.1 inches of rainfall annually with predominantly loam soil. Summer highs average 82ยฐF, so choose short-season varieties of Radish to ensure they mature before fall.

Conejos County, CO (Zone 4b) Short season
100 days
Last Spring Frost June 9
100 growing days
First Fall Frost September 17

Conejos County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (56 days to spare)
Transplant: May 30 🍅 Harvest: Jun 27 – Jul 18
Recommended (50%) ✓ Fits season (51 days to spare)
Transplant: Jun 9 🍅 Harvest: Jul 7 – Jul 28
Safe Start (90%) ✓ Fits season (50 days to spare)
Transplant: Jun 22 🍅 Harvest: Jul 20 – Aug 10

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 Conejos County

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

Soil pH

Your soil pH (6.6โ€“7.8) is more alkaline than Radish prefers (6.0โ€“7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Conejos County is excellent for Radish โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Radish.

How to Plant Radish

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

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Succession Planting Radish

5
successive plantings in your 100-day season

Sow every 2.4 weeks. Last sowing by Aug 13 to harvest before frost.

For a dedicated fall crop, sow by Jun 25.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” 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 โ€” 1.8" 0" โ„๏ธ Dormant
Feb โ€” 1.3" 0" โ„๏ธ Dormant
Mar โ€” 2" 0" โ„๏ธ Dormant
Apr โ€” 2.8" 0" โ„๏ธ Dormant
May โ€” 2.7" 0" โ„๏ธ Dormant
Jun 2.2" 1.7" 0.5" ๐Ÿ’ง Light watering
Jul 2.2" 1.8" 0.4" ๐Ÿ’ง Light watering
Aug 2.2" 2.5" 0" โœ… Rainfall sufficient
Sep 2.2" 2.1" 0.1" ๐Ÿ’ง Light watering
Oct โ€” 2.3" 0" โ„๏ธ Dormant
Nov โ€” 1.7" 0" โ„๏ธ Dormant
Dec โ€” 1.5" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Junโ€“Sep in Conejos County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~328 GDD — county provides 1,150 GDD Excellent fit

Radish Planting Timeline โ€” Conejos County, CO

Radish Planting Calendar

Activity When Date Range
Direct Sow June 2 Jun 2 โ€“ Jun 23
Harvest June 30 Jun 30 โ€“ Jul 21
Fall Sowing June 25 Jun 25 โ€“ Jul 9

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.5"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

22โ€“35 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 4b

๐Ÿ“† Growing Season

100 days in Conejos County

Growing Tips for Radish in Conejos County

Direct sow Radish outdoors after June 09 in Conejos County when soil has warmed and frost danger has passed.

Your generous 100.0-day season in Conejos 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 Conejos County, CO?

Conejos County is in Zone 4b with an average last frost of June 9. Plan your Radish planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Conejos County, CO?

Conejos County, Colorado is in USDA Hardiness Zone 4b. The average last spring frost is June 9 and first fall frost is September 17.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Conejos County gardeners in Zone 4b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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