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When to Plant Turnip in Adams County, CO

Adams County, Colorado Zone 6a May

Adams County, Colorado gardeners: here's your May plan

May is a pivotal month for Adams County, Colorado gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 4
Avg. first frost October 5
Soil temp (4") 40°F
Watering High
Pest pressure Low
Daylight 14.2 hrs
Get ahead of June
  • First harvests: turnip

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Turnips are a fast-growing cool-season root vegetable with edible roots and greens. Baby turnips are sweet and tender while mature ones are more pungent.

Adams County, Colorado is in USDA Zone 6a. The average last spring frost is May 4 and the first fall frost is October 5, giving you a growing season of approximately 154 days.

At an elevation of 5,827 feet, Adams County receives approximately 23.9 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Turnip during the growing season.

Adams County, CO (Zone 6a) Moderate season
154 days
Last Spring Frost May 4
154 growing days
First Fall Frost October 5

Adams County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (74 days to spare)
Transplant: Apr 29 🍅 Harvest: Jun 10 – Jul 15
Recommended (50%) ✓ Fits season (77 days to spare)
Transplant: May 4 🍅 Harvest: Jun 15 – Jul 20
Safe Start (90%) ✓ Fits season (72 days to spare)
Transplant: May 21 🍅 Harvest: Jul 2 – Aug 6

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 Adams County

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

Soil pH

Your soil pH (6.6–7.7) is more alkaline than Turnip prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Adams County is excellent for Turnip — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Turnip.

How to Plant Turnip

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 Turnip

4
successive plantings in your 154-day season

Sow every 4.6 weeks. Last sowing by Aug 06 to harvest before frost.

For a dedicated fall crop, sow by Jul 27.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 573 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Turnip

Turnip needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Turnip Needs Rainfall You Supplement Action
Jan 1.8" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 2.4" 0" ❄️ Dormant
May 4.3" 2.5" 1.8" 💧 Light watering
Jun 4.3" 1.6" 2.7" 🚿 Regular watering
Jul 4.3" 2.1" 2.2" 🚿 Regular watering
Aug 4.3" 2.8" 1.5" 💧 Light watering
Sep 4.3" 1.8" 2.5" 🚿 Regular watering
Oct 4.3" 2.3" 2" 💧 Light watering
Nov 1.5" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

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

Turnip 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.

Turnip needs ~762 GDD — county provides 2,348 GDD Excellent fit

Turnip Planting Timeline — Adams County, CO

Turnip Planting Calendar

Activity When Date Range
Direct Sow April 20 Apr 20 – May 11
Harvest June 1 Jun 1 – Jul 6
Fall Sowing July 27 Jul 27 – Aug 10

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6a

📆 Growing Season

154 days in Adams County

Growing Tips for Turnip in Adams County

Direct sow Turnip outdoors after May 04 in Adams County when soil has warmed and frost danger has passed.

Your generous 154.0-day season in Adams County allows multiple plantings of Turnip. Sow every 20.0 days for continuous harvest.

Common pests for Turnip in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

Adams County receives only 24" of rain annually. Turnip needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow in early spring or late summer. Harvest when roots are 2-3 inches in diameter for best flavor. Both the roots and the greens are nutritious and edible.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Turnip in Adams County, CO?

Adams County is in Zone 6a with an average last frost of May 4. Plan your Turnip planting based on this frost date — see the calendar above for exact timing.

What planting zone is Adams County, CO?

Adams County, Colorado is in USDA Hardiness Zone 6a. The average last spring frost is May 4 and first fall frost is October 5.

🌱

Your Adams County Garden Planner — Free

A 24-page printable planner built for Adams 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 Adams County, CO. 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.