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When to Plant Basil in Osage County, OK

Osage County, Oklahoma Zone 7a May

What to do in May

Your garden in Osage County, Oklahoma is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost April 6
Avg. first frost October 27
Soil temp (4") 69°F
Watering Moderate
Pest pressure Moderate
Daylight 14 hrs
  1. Begin indoor sowing: basil

    Your window is short. These crops want several weeks of indoor growth before they go outside.

Before June arrives, get these ready
  • First harvests: 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.

Osage County, Oklahoma is in USDA Zone 7a. The average last spring frost is April 6 and the first fall frost is October 27, giving you a growing season of approximately 204 days.

At an elevation of 492 feet, Osage County receives approximately 23.1 inches of rainfall annually with predominantly loam soil. Summer highs average 88°F, providing good warmth for Basil during the growing season.

Osage County, OK (Zone 7a) Long season
204 days
Last Spring Frost April 6
204 growing days
First Fall Frost October 27

Osage County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (72 days to spare)
Start indoors: Feb 8 Transplant: Apr 12 🍅 Harvest: Jun 7 – Aug 9
Recommended (50%) ✓ Fits season (71 days to spare)
Start indoors: Feb 16 Transplant: Apr 20 🍅 Harvest: Jun 15 – Aug 17
Safe Start (90%) ✓ Fits season (74 days to spare)
Start indoors: Mar 1 Transplant: May 3 🍅 Harvest: Jun 28 – Aug 30

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 Osage County

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

Soil pH

Your soil pH (6.3–7.2) overlaps with Basil's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.3%) — Basil will thrive.

How to Plant Basil

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

Succession Planting Basil

4
successive plantings in your 204-day season

Sow every 5.7 weeks. Last sowing by Aug 13 to harvest before frost.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
0.5″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 271 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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 0.5" 0" ❄️ Dormant
Feb 0.7" 0" ❄️ Dormant
Mar 1.6" 0" ❄️ Dormant
Apr 2.6" 2.8" 0" ✅ Rainfall sufficient
May 2.6" 3.6" 0" ✅ Rainfall sufficient
Jun 2.6" 3.6" 0" ✅ Rainfall sufficient
Jul 2.6" 2.8" 0" ✅ Rainfall sufficient
Aug 2.6" 2.6" 0" ✅ Rainfall sufficient
Sep 2.6" 1.9" 0.7" 💧 Light watering
Oct 2.6" 1.5" 1.1" 💧 Light watering
Nov 0.9" 0" ❄️ Dormant
Dec 0.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Osage 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 3,264 GDD Excellent fit

Basil Planting Timeline — Osage County, OK

Basil Planting Calendar

Activity When Date Range
Start Indoors February 16 Feb 16 – Mar 2
Transplant Outdoors April 20 Apr 20 – May 4
Direct Sow April 13 Apr 13 – May 4
Harvest June 15 Jun 15 – Aug 17

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.6"/week · Only during dry spells

📅 Days to Maturity

50–75 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

204 days in Osage County

Growing Tips for Basil in Osage County

Direct sow Basil outdoors after April 06 in Osage 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 Osage County, OK?

Osage County is in Zone 7a with an average last frost of April 6. Plan your Basil planting based on this frost date — see the calendar above for exact timing.

What planting zone is Osage County, OK?

Osage County, Oklahoma is in USDA Hardiness Zone 7a. The average last spring frost is April 6 and first fall frost is October 27.

🌱

Your Osage County Garden Planner — Free

A 24-page printable planner built for Osage County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Osage County, OK. 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.