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When to Plant Tomatoes in Jersey 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.

Jersey County, Illinois is in USDA Zone 6a. The average last spring frost is April 11 and the first fall frost is October 21, giving you a growing season of approximately 193 days.

At an elevation of 1,202 feet, Jersey County receives approximately 34.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88ยฐF, providing good warmth for Tomatoes during the growing season.

Jersey County, IL (Zone 6a) Moderate season
193 days
Last Spring Frost April 11
193 growing days
First Fall Frost October 21

Jersey County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (48 days to spare)
Start indoors: Feb 7 Transplant: Apr 18 🍅 Harvest: Jun 20 – Aug 29
Recommended (50%) ✓ Fits season (46 days to spare)
Start indoors: Feb 14 Transplant: Apr 25 🍅 Harvest: Jun 27 – Sep 5
Safe Start (90%) ✓ Fits season (51 days to spare)
Start indoors: Feb 23 Transplant: May 4 🍅 Harvest: Jul 6 – Sep 14

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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 428 gal / 100 sq ft
Tomatoes needs ~1,160 GDD — county provides 3,088 GDD Excellent fit

Tomatoes Planting Timeline โ€” Jersey County, IL

Tomatoes Planting Calendar

Activity When Date Range
Start Indoors February 14 Feb 14 โ€“ Feb 28
Transplant Outdoors April 25 Apr 25 โ€“ May 9
Direct Sow April 18 Apr 18 โ€“ May 9
Harvest June 27 Jun 27 โ€“ Sep 5

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

Month-by-Month Timeline

MonthActivities
January โ€”
February Start Indoors
March โ€”
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

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

60โ€“85 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 6a

Growing Season

193 days

Growing Tips for Jersey County

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 Jersey County, IL?

Jersey County is in Zone 6a with an average last frost of April 11. Plan your Tomatoes planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Jersey County, IL?

Jersey County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 11 and first fall frost is October 21.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Jersey County gardeners in Zone 6a 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 Jersey County, IL. Local conditions may vary. Last updated: April 2026.