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When to Plant Basil in Prowers County, CO

Prowers County, Colorado Zone 6a May

May to-do list for Prowers County, Colorado

Welcome to May in Zone 6a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 30
Avg. first frost October 10
Soil temp (4") 44°F
Watering High
Pest pressure Low
Daylight 14.1 hrs
  1. Move basil into the garden

    Your last frost (April 30) has passed. These warm-season crops can handle outdoor soil now.

  2. Outdoor sowing time: basil

    Rake a smooth bed, make a shallow furrow, drop seeds at the spacing on the packet, water gently, walk away.

June will be here before you know it — start on
  • Starting indoors: basil

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Basil is a fragrant warm-season herb essential to Italian and Thai cuisines. It comes in many varieties including sweet, Thai, purple, and lemon types.

Prowers County, Colorado is in USDA Zone 6a. The average last spring frost is April 30 and the first fall frost is October 10, giving you a growing season of approximately 163 days.

At an elevation of 6,074 feet, Prowers County receives approximately 24.7 inches of rainfall annually with predominantly loam soil. Summer highs average 88°F, providing good warmth for Basil during the growing season.

Prowers County, CO (Zone 6a) Moderate season
163 days
Last Spring Frost April 30
163 growing days
First Fall Frost October 10
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Prowers County Soil Profile

Soil Type

Loam

Soil pH

6.2-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (30 days to spare)
Start indoors: Mar 8 Transplant: May 10 🍅 Harvest: Jul 5 – Sep 6
Recommended (50%) ✓ Fits season (30 days to spare)
Start indoors: Mar 12 Transplant: May 14 🍅 Harvest: Jul 9 – Sep 10
Safe Start (90%) ✓ Fits season (31 days to spare)
Start indoors: Mar 25 Transplant: May 27 🍅 Harvest: Jul 22 – Sep 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 Prowers County

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

Soil pH

Your soil pH (6.2–8.3) is more alkaline than Basil prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.1%). Annual compost additions will help Basil.

How to Plant Basil

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Basil

3
successive plantings in your 163-day season

Sow every 5.7 weeks. Last sowing by Jul 27 to harvest before frost.

Plant Water Budget

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

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

Monthly Watering Guide for Basil

Basil needs approximately 0.6 inches of water per week (2.6" per month). Here's how your county's rainfall compares month by month.

Month Basil Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 2.6" 2.8" 0" ✅ Rainfall sufficient
May 2.6" 2.6" 0" ✅ Rainfall sufficient
Jun 2.6" 1.5" 1.1" 💧 Light watering
Jul 2.6" 2.1" 0.5" 💧 Light watering
Aug 2.6" 2.9" 0" ✅ Rainfall sufficient
Sep 2.6" 2.3" 0.3" 💧 Light watering
Oct 2.6" 2.4" 0.2" 💧 Light watering
Nov 1.6" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

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

Basil 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.

Basil needs ~1,000 GDD — county provides 2,608 GDD Excellent fit

Basil Planting Timeline — Prowers County, CO

Basil Planting Calendar

Activity When Date Range
Start Indoors March 12 Mar 12 – Mar 26
Transplant Outdoors May 14 May 14 – May 28
Direct Sow May 7 May 7 – May 28
Harvest July 9 Jul 9 – Sep 10

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April
May Transplant Outdoors Direct Sow
June
July Harvest
August Harvest
September Harvest
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.6"/week · Natural rainfall sufficient

📅 Days to Maturity

50–75 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6a

📆 Growing Season

163 days in Prowers County

Growing Tips for Basil in Prowers County

Direct sow Basil outdoors after April 30 in Prowers County when soil has warmed and frost danger has passed.

General growing tips

Start seeds indoors or direct sow after last frost. Pinch flower buds to extend leaf production. Harvest leaves from the top down, cutting just above a leaf pair.

Companion Planting

Good Companions

Avoid Planting Near

  • Rue
  • Sage

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Basil Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Let flower spikes dry brown on the plant.
Storage Store airtight; viable 5 years at 35°F, under 45% humidity.

Isolate 150 ft between varieties. Different basil species can cross.

Frequently Asked Questions

When should I plant Basil in Prowers County, CO?

Prowers County is in Zone 6a with an average last frost of April 30. Plan your Basil planting based on this frost date — see the calendar above for exact timing.

What planting zone is Prowers County, CO?

Prowers County, Colorado is in USDA Hardiness Zone 6a. The average last spring frost is April 30 and first fall frost is October 10.

🌱

Your Prowers County Garden Planner — Free

A 24-page printable planner built for Prowers 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 Prowers 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.