Blog

When to Plant Tomatoes in Greene County, IL

Tomatoes are the most popular home garden crop, available in thousands of varieties from tiny cherries to massive beefsteaks. They are warm-season plants needing full sun.

Greene County, Illinois is in USDA Zone 5b. The average last spring frost is April 13 and the first fall frost is October 21, giving you a growing season of approximately 191 days.

At an elevation of 1,248 feet, Greene County receives approximately 37 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86ยฐF, providing good warmth for Tomatoes during the growing season.

Greene County, IL (Zone 5b) Moderate season
191 days
Last Spring Frost April 13
191 growing days
First Fall Frost October 21

Greene County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (43 days to spare)
Start indoors: Feb 10 Transplant: Apr 21 🍅 Harvest: Jun 23 – Sep 1
Recommended (50%) ✓ Fits season (44 days to spare)
Start indoors: Feb 16 Transplant: Apr 27 🍅 Harvest: Jun 29 – Sep 7
Safe Start (90%) ✓ Fits season (43 days to spare)
Start indoors: Feb 28 Transplant: May 9 🍅 Harvest: Jul 11 – Sep 19

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 Greene County

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

Soil pH

Your soil pH (6.1โ€“6.7) is within Tomatoes's preferred range (6.0โ€“7.0).

Soil Texture

The silt loam soil in Greene County is excellent for Tomatoes โ€” good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Tomatoes.

Organic Matter

Organic matter is excellent (4.5%) โ€” Tomatoes will thrive.

How to Plant Tomatoes

0.5"
Planting Depth
24"
Between Plants
36"
Between Rows

Succession Planting Tomatoes

3
successive plantings in your 191-day season

Sow every 6.9 weeks. Last sowing by Jul 28 to harvest before frost.

Plant Water Budget

Plant needs
1.2″/week
Rainfall provides
0.8″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 1,523 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Tomatoes needs ~1,051 GDD — county provides 2,769 GDD Excellent fit

Tomatoes Planting Timeline โ€” Greene County, IL

Tomatoes Planting Calendar

Activity When Date Range
Start Indoors February 16 Feb 16 โ€“ Mar 2
Transplant Outdoors April 27 Apr 27 โ€“ May 11
Direct Sow April 20 Apr 20 โ€“ May 11
Harvest June 29 Jun 29 โ€“ Sep 7

Plant 0.5" deep ยท 24" apart ยท Rows 36" apart

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1.2"/week ยท 2-3 times/week

๐Ÿ“… Days to Maturity

60โ€“85 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 5b

๐Ÿ“† Growing Season

191 days in Greene County

Growing Tips for Tomatoes in Greene County

Direct sow Tomatoes outdoors after April 13 in Greene County when soil has warmed and frost danger has passed.

Common pests for Tomatoes in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 6-8 weeks before last frost. Bury transplants deep to encourage rooting along the stem. Provide consistent moisture to prevent blossom end rot and cracking.

Companion Planting

Good Companions

Avoid Planting Near

  • Cabbage
  • Fennel
  • Potatoes

Level Up Your Garden

๐ŸŒพ Save Your Own Tomatoes Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Scoop seeds from ripe fruit; ferment 2-3 days to remove gel coating.
Storage Store airtight; viable 4-6 years at 35ยฐF, under 45% humidity.

Isolate 25 ft between varieties for purity. Use open-pollinated varieties for true-to-type seeds.

Frequently Asked Questions

When should I plant Tomatoes in Greene County, IL?

Greene County is in Zone 5b with an average last frost of April 13. Plan your Tomatoes planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Greene County, IL?

Greene County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 13 and first fall frost is October 21.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Greene County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Greene County, IL. Local conditions may vary. Last updated: April 2026.