When to plant Tomatoes in Madison County, IA
In Madison County, plant Tomatoes in spring between May 1 and May 22, once soil temps hold above 50°F. Madison County's last frost averages April 24, so time plantings around the expected last-frost window for best survival. For a fall crop, sow between and — roughly 60–85 days before the first frost on October 11.
When to Plant Tomatoes in Madison County, IA
What to do in June
June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Madison County, Iowa.
-
Get tomatoes seeds going inside
Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.
July will be here before you know it — start on
- 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.
Madison County, Iowa is in USDA Zone 5b. The average last spring frost is April 24 and the first fall frost is October 11, giving you a growing season of approximately 170 days.
At an elevation of 1,022 feet, Madison County receives approximately 40.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Tomatoes to ensure they mature before fall.
Madison County Soil Profile
Soil Type
Silt Loam
Soil pH
6.3-6.9
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 Madison County
How your county's soil matches Tomatoes's growing requirements.
Soil pH
Your soil pH (6.3–6.9) is within Tomatoes's preferred range (6.0–7.0).
Soil Texture
The silt loam soil in Madison County is excellent for Tomatoes — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.3%) — Tomatoes will thrive.
How to Plant Tomatoes
Succession Planting Tomatoes
Sow every 6.9 weeks. Last sowing by Jul 18 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 | — | 1.9" | 0" | ❄️ Dormant |
| Feb | — | 2" | 0" | ❄️ Dormant |
| Mar | — | 2.7" | 0" | ❄️ Dormant |
| Apr | 5.2" | 4" | 1.2" | 💧 Light watering |
| May | 5.2" | 5.4" | 0" | ✅ Rainfall sufficient |
| Jun | 5.2" | 5" | 0.2" | 💧 Light watering |
| Jul | 5.2" | 4" | 1.2" | 💧 Light watering |
| Aug | 5.2" | 3.7" | 1.5" | 💧 Light watering |
| Sep | 5.2" | 3.8" | 1.4" | 💧 Light watering |
| Oct | 5.2" | 3.4" | 1.8" | 💧 Light watering |
| Nov | — | 2.4" | 0" | ❄️ Dormant |
| Dec | — | 2.4" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Madison 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 — Madison County, IA
Tomatoes Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 27 | Feb 27 – Mar 13 |
| Transplant Outdoors | May 8 | May 8 – May 22 |
| Direct Sow | May 1 | May 1 – May 22 |
| Harvest | July 10 | Jul 10 – Sep 18 |
Plant 0.5" deep · 24" apart · Rows 36" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.2"/week · Only during dry spells
📅 Days to Maturity
60–85 days
🧪 Soil pH
Needs 6–7 · Your soil: ideal
🗺️ USDA Zone
Zone 5b
📆 Growing Season
170 days in Madison County
Growing Tips for Tomatoes in Madison County
Direct sow Tomatoes outdoors after April 24 in Madison 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 Madison County, IA?
Madison County is in Zone 5b with an average last frost of April 24. Plan your Tomatoes planting based on this frost date — see the calendar above for exact timing.
What planting zone is Madison County, IA?
Madison County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 24 and first fall frost is October 11.
When should I plant Tomatoes in Madison County, IA?
In Madison County, IA, plant Tomatoes after the last frost (around April 24) and before the first frost (around October 11). Best results when soil holds above 50°F.
What growing zone is Madison County, IA for Tomatoes?
Madison County sits in USDA Zone 5b. Tomatoes grows reliably in zones 3a through 11b, so it's a good fit here.
Can Tomatoes grow in Madison County's climate?
Yes — Tomatoes grows well in Madison County's temperate climate. Madison County averages a 170-day frost-free season, with last frost around April 24 and first frost around October 11.
Your Madison County Garden Planner — Free
A 22-page printable planner built for Madison County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.