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When to plant Basil in Valmeyer, IL

In Valmeyer, plant Basil in spring between April 21 and May 12, once soil temps hold above 50°F. Valmeyer's last frost averages April 14, so most warm-season crops establish quickly once soil holds above 60°F. For a fall crop, sow between and — roughly 50–75 days before the first frost on October 24.

When to Plant Basil in Valmeyer, IL

Basil
Monroe County, Illinois Zone 7a June

June to-do list for Monroe County, Illinois

A quick June briefing for Monroe County, Illinois gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 14
Avg. first frost October 24
Soil temp (4") 72°F
Watering Low
Pest pressure High
Daylight 14.6 hrs
  1. Fire up the seed-starting tray: basil

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

  2. Start harvesting basil

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

Get ahead of July
  • 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.

Valmeyer, Illinois is in USDA Zone 7a. The average last spring frost is April 14 and the first fall frost is October 24, giving you a growing season of approximately 193 days.

At an elevation of 1,278 feet, Monroe County receives approximately 34.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Basil during the growing season.

Valmeyer, IL (Zone 7a) Moderate season
193 days
Last Spring Frost April 14
193 growing days
First Fall Frost October 24

Valmeyer Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.8

Drainage

Well Drained

Basil Planting Risk Windows

Early Start (70% safe) ✓ Fits season (61 days to spare)
Start indoors: Feb 16 Transplant: Apr 20 🍅 Harvest: Jun 15 – Aug 17
Recommended (50%) ✓ Fits season (60 days to spare)
Start indoors: Feb 24 Transplant: Apr 28 🍅 Harvest: Jun 23 – Aug 25
Safe Start (90%) ✓ Fits season (62 days to spare)
Start indoors: Mar 7 Transplant: May 9 🍅 Harvest: Jul 4 – Sep 5

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 Valmeyer

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

Soil pH

Your soil pH (5.7–6.8) overlaps with Basil's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.2%) — 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 193-day season

Sow every 5.7 weeks. Last sowing by Aug 10 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 1.2" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 2.6" 3.1" 0" ✅ Rainfall sufficient
May 2.6" 3.6" 0" ✅ Rainfall sufficient
Jun 2.6" 4.1" 0" ✅ Rainfall sufficient
Jul 2.6" 4.1" 0" ✅ Rainfall sufficient
Aug 2.6" 4" 0" ✅ Rainfall sufficient
Sep 2.6" 2.9" 0" ✅ Rainfall sufficient
Oct 2.6" 2.7" 0" ✅ Rainfall sufficient
Nov 2.4" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Monroe 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 3,088 GDD Excellent fit

Basil Planting Timeline — Valmeyer, 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

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 7a

📆 Growing Season

193 days in Monroe County

Growing Tips for Basil in Valmeyer

Direct sow Basil outdoors after April 14 in Monroe 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.

When should I plant Basil in Valmeyer, IL?

In Valmeyer, IL, plant Basil after the last frost (around April 14) and before the first frost (around October 24). Best results when soil holds above 50°F.

What growing zone is Valmeyer, IL for Basil?

Valmeyer sits in USDA Zone 7a. Basil grows reliably in zones 4a through 11b, so it's a good fit here.

Can Basil grow in Valmeyer's climate?

Yes — Basil grows well in Valmeyer's temperate climate. Valmeyer averages a 193-day frost-free season, with last frost around April 14 and first frost around October 24.

🌱

Your Monroe County Garden Planner — Free

A 22-page printable planner built for Monroe 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.

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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 Monroe County, IL. Local conditions may vary. Last updated: June 2026.