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When to plant Tomatoes in Stephenson County County,

Stephenson County County's spring Tomatoes window runs April 30 through May 21. time plantings around the expected last-frost window for best survival.

When to Plant Tomatoes in Stephenson County, IL

Tomatoes

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.

Stephenson County, Illinois is in USDA Zone 5a. The average last spring frost is April 23 and the first fall frost is October 13, giving you a growing season of approximately 173 days.

At an elevation of 1,345 feet, Stephenson County receives approximately 36.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Tomatoes during the growing season.

Stephenson County, IL (Zone 5a) Moderate season
173 days
Last Spring Frost April 23
173 growing days
First Fall Frost October 13

Stephenson County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.1

Drainage

Well Drained

How Much Tomatoes to Grow

10-15 lbs
Average yield per plant
3
Plants per person
6 sq ft
Space per person

For a family of 4, plant approximately 12 tomatoes plants in about 24 sq ft. In Stephenson County's 173-day season, you'll have plenty of time for a full harvest. Plan your garden layout →

Monthly Watering Guide for Tomatoes

Tomatoes needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Tomatoes Needs Rainfall You Supplement Action
Jan 1.7" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 4.3" 3.3" 1" 💧 Light watering
May 4.3" 4.7" 0" ✅ Rainfall sufficient
Jun 4.3" 4" 0.3" 💧 Light watering
Jul 4.3" 4.1" 0.2" 💧 Light watering
Aug 4.3" 3.9" 0.4" 💧 Light watering
Sep 4.3" 3.5" 0.8" 💧 Light watering
Oct 4.3" 2.4" 1.9" 💧 Light watering
Nov 2.3" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Stephenson County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Tomatoes Planting Timeline — Stephenson County, IL

Tomatoes Planting Calendar

Activity When Date Range
Start Indoors February 26 Feb 26 – Mar 12
Transplant Outdoors May 7 May 7 – May 21
Direct Sow April 30 Apr 30 – May 21
Harvest July 9 Jul 9 – Sep 17

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

60–85 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 5a

📆 Growing Season

173 days in Stephenson County

Growing Tips for Stephenson 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

Check more plant combinations with our Companion Planting Checker →

🌾 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 35°F, 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 Stephenson County, IL?

Stephenson County is in Zone 5a with an average last frost of April 23. Plan your Tomatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Stephenson County, IL?

Stephenson County, Illinois is in USDA Hardiness Zone 5a. The average last spring frost is April 23 and first fall frost is October 13.

When should I plant Tomatoes in Stephenson County County, ?

In Stephenson County County, , plant Tomatoes after the last frost (around April 23) and before the first frost (around October 13). Best results when soil holds above 50°F.

What growing zone is Stephenson County County, for Tomatoes?

Stephenson County County sits in USDA Zone 5a. Tomatoes grows reliably in zones 3a through 11b, so it's a good fit here.

Can Tomatoes grow in Stephenson County County's climate?

Yes — Tomatoes grows well in Stephenson County County's temperate climate. Stephenson County County averages a 173-day frost-free season, with last frost around April 23 and first frost around October 13.

🌱

Your Stephenson County Garden Planner — Free

A 22-page printable planner built for Stephenson County (Zone 5a). 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 Stephenson 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.