When to plant Tomatoes in Jefferson County County,
Jefferson County County's climate puts the Tomatoes spring window between April 16 and May 7. time plantings around the expected last-frost window for best survival.
When to Plant Tomatoes in Jefferson County, IL
What to do in June
Here's what deserves your attention in Jefferson County, Illinois this month. Everything below is tailored to Zone 6b and timed around your local frost dates.
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Start tomatoes indoors
These need a head start before your last frost (April 9). Sow into cells now so you're ready to transplant in a few weeks.
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Pick tomatoes
Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.
To set up a strong July, finish these tasks
- First harvests: 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.
Jefferson County, Illinois is in USDA Zone 6b. The average last spring frost is April 9 and the first fall frost is October 20, giving you a growing season of approximately 194 days.
At an elevation of 509 feet, Jefferson County receives approximately 34 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Tomatoes during the growing season.
Jefferson County Soil Profile
Soil Type
Silt Loam
Soil pH
6.1-7.1
Drainage
Well Drained
Tomatoes Planting Risk Windows
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 Jefferson County
How your county's soil matches Tomatoes's growing requirements.
Soil pH
Your soil pH (6.1–7.1) overlaps with Tomatoes's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Jefferson County is excellent for Tomatoes — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.2%) — Tomatoes will thrive.
How to Plant Tomatoes
Succession Planting Tomatoes
Sow every 6.9 weeks. Last sowing by Jul 27 to harvest before frost.
Tomatoes Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Tomatoes
Tomatoes needs approximately 1.2 inches of water per week (5.2" per month). Here's how your county's rainfall compares month by month.
| Month | Tomatoes Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.4" | 0" | ❄️ Dormant |
| Mar | — | 2.5" | 0" | ❄️ Dormant |
| Apr | 5.2" | 3.2" | 2" | 💧 Light watering |
| May | 5.2" | 4.3" | 0.9" | 💧 Light watering |
| Jun | 5.2" | 3.9" | 1.3" | 💧 Light watering |
| Jul | 5.2" | 3.8" | 1.4" | 💧 Light watering |
| Aug | 5.2" | 3.4" | 1.8" | 💧 Light watering |
| Sep | 5.2" | 3" | 2.2" | 💧 Light watering |
| Oct | 5.2" | 2.9" | 2.3" | 💧 Light watering |
| Nov | — | 2.3" | 0" | ❄️ Dormant |
| Dec | — | 1.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Jefferson County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Tomatoes 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.
Tomatoes Planting Timeline — Jefferson County, IL
Tomatoes Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 12 | Feb 12 – Feb 26 |
| Transplant Outdoors | April 23 | Apr 23 – May 7 |
| Direct Sow | April 16 | Apr 16 – May 7 |
| Harvest | June 25 | Jun 25 – Sep 3 |
Plant 0.5" deep · 24" apart · Rows 36" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | — |
| April | Transplant Outdoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | Harvest |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.2"/week · 1-2 times/week
📅 Days to Maturity
60–85 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 6b
📆 Growing Season
194 days in Jefferson County
Growing Tips for Tomatoes in Jefferson County
Direct sow Tomatoes outdoors after April 09 in Jefferson 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
Check more plant combinations with our Companion Planting Checker →
Isolate 25 ft between varieties for purity. Use open-pollinated varieties for true-to-type seeds.
Tomatoes in Other Locations
Frequently Asked Questions
When should I plant Tomatoes in Jefferson County, IL?
Jefferson County is in Zone 6b with an average last frost of April 9. Plan your Tomatoes planting based on this frost date — see the calendar above for exact timing.
What planting zone is Jefferson County, IL?
Jefferson County, Illinois is in USDA Hardiness Zone 6b. The average last spring frost is April 9 and first fall frost is October 20.
When should I plant Tomatoes in Jefferson County, ?
In Jefferson County, , plant Tomatoes after the last frost (around April 9) and before the first frost (around October 20). Best results when soil holds above 50°F.
What growing zone is Jefferson County, for Tomatoes?
Jefferson County sits in USDA Zone 6b. Tomatoes grows reliably in zones 3a through 11b, so it's a good fit here.
Can Tomatoes grow in Jefferson County's climate?
Yes — Tomatoes grows well in Jefferson County's temperate climate. Jefferson County averages a 194-day frost-free season, with last frost around April 9 and first frost around October 20.
Your Jefferson County Garden Planner — Free
A 22-page printable planner built for Jefferson County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.