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When to plant Basil in Douglas County County,

Plant Basil in Douglas County County, when soil hits 50°F — usually April 21. Continue planting through May 12 for the spring crop.

When to Plant Basil in Douglas County, IL

Basil
Douglas County, Illinois Zone 6a June

Your June game plan for Douglas County, Illinois

Your garden in Douglas County, Illinois is working on a schedule, even when you're not. Here's where you should be this June.

Avg. last frost April 14
Avg. first frost October 17
Soil temp (4") 68°F
Watering Moderate
Pest pressure High
Daylight 14.8 hrs
  1. Begin indoor sowing: basil

    Label every cell. You will absolutely forget which is which otherwise.

  2. It's harvest week for basil

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

July prep starts now
  • 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.

Douglas County, Illinois is in USDA Zone 6a. The average last spring frost is April 14 and the first fall frost is October 17, giving you a growing season of approximately 186 days.

At an elevation of 1,036 feet, Douglas County receives approximately 30.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Basil during the growing season.

Douglas County, IL (Zone 6a) Moderate season
186 days
Last Spring Frost April 14
186 growing days
First Fall Frost October 17
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Douglas County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.2

Drainage

Well Drained

Basil Planting Risk Windows

Early Start (70% safe) ✓ Fits season (53 days to spare)
Start indoors: Feb 19 Transplant: Apr 23 🍅 Harvest: Jun 18 – Aug 20
Recommended (50%) ✓ Fits season (53 days to spare)
Start indoors: Feb 24 Transplant: Apr 28 🍅 Harvest: Jun 23 – Aug 25
Safe Start (90%) ✓ Fits season (53 days to spare)
Start indoors: Mar 10 Transplant: May 12 🍅 Harvest: Jul 7 – Sep 8

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 Douglas County

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

Soil pH

Your soil pH (6.2–7.2) overlaps with Basil's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Douglas 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 186-day season

Sow every 5.7 weeks. Last sowing by Aug 03 to harvest before frost.

Basil Water Budget

Plant needs
0.6″/week
Rainfall provides
0.7″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 1.5" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2.6" 2.9" 0" ✅ Rainfall sufficient
May 2.6" 3.6" 0" ✅ Rainfall sufficient
Jun 2.6" 3.6" 0" ✅ Rainfall sufficient
Jul 2.6" 3.7" 0" ✅ Rainfall sufficient
Aug 2.6" 3" 0" ✅ Rainfall sufficient
Sep 2.6" 2.9" 0" ✅ Rainfall sufficient
Oct 2.6" 2.6" 0" ✅ Rainfall sufficient
Nov 1.9" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Douglas 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 ~953 GDD — county provides 2,836 GDD Excellent fit

Basil Planting Timeline — Douglas County, IL

Basil Planting Calendar

Activity When Date Range
Start Indoors February 24 Feb 24 – Mar 10
Transplant Outdoors April 28 Apr 28 – May 12
Direct Sow April 21 Apr 21 – May 12
Harvest June 23 Jun 23 – Aug 25

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
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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: acceptable

🗺️ USDA Zone

Zone 6a

📆 Growing Season

186 days in Douglas County

Growing Tips for Basil in Douglas County

Direct sow Basil outdoors after April 14 in Douglas 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 Douglas County, IL?

Douglas County is in Zone 6a with an average last frost of April 14. Plan your Basil planting based on this frost date — see the calendar above for exact timing.

What planting zone is Douglas County, IL?

Douglas County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 14 and first fall frost is October 17.

When should I plant Basil in Douglas County, ?

In Douglas County, , plant Basil after the last frost (around April 14) and before the first frost (around October 17). Best results when soil holds above 50°F.

What growing zone is Douglas County, for Basil?

Douglas County sits in USDA Zone 6a. Basil grows reliably in zones 4a through 11b, so it's a good fit here.

Can Basil grow in Douglas County's climate?

Yes — Basil grows well in Douglas County's temperate climate. Douglas County averages a 186-day frost-free season, with last frost around April 14 and first frost around October 17.

🌱

Your Douglas County Garden Planner — Free

A 22-page printable planner built for Douglas 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 Douglas County, IL. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.