When to Plant Tomatoes in Monroe County, MO
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.
Monroe County, Missouri is in USDA Zone 5b. The average last spring frost is April 14 and the first fall frost is October 21, giving you a growing season of approximately 190 days.
At an elevation of 1,128 feet, Monroe County receives approximately 35.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Tomatoes to ensure they mature before fall.
Monroe County Soil Profile
Soil Type
Silt Loam
Soil pH
5.7-6.6
Drainage
Well Drained
Plant 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 Monroe County
How your county's soil matches Tomatoes's growing requirements.
Soil pH
Your soil pH (5.7–6.6) overlaps with Tomatoes's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Monroe County is excellent for Tomatoes — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Tomatoes.
Organic Matter
Organic matter is moderate (2.8%). Annual compost additions will help Tomatoes.
How to Plant Tomatoes
Succession Planting Tomatoes
Sow every 6.9 weeks. Last sowing by Jul 28 to harvest before frost.
Plant 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 | — | 1.6" | 0" | ❄️ Dormant |
| Feb | — | 1.7" | 0" | ❄️ Dormant |
| Mar | — | 2.2" | 0" | ❄️ Dormant |
| Apr | 5.2" | 3.7" | 1.5" | 💧 Light watering |
| May | 5.2" | 3.6" | 1.6" | 💧 Light watering |
| Jun | 5.2" | 4.9" | 0.3" | 💧 Light watering |
| Jul | 5.2" | 3.9" | 1.3" | 💧 Light watering |
| Aug | 5.2" | 3.7" | 1.5" | 💧 Light watering |
| Sep | 5.2" | 3.3" | 1.9" | 💧 Light watering |
| Oct | 5.2" | 2.6" | 2.6" | 🚿 Regular watering |
| Nov | — | 2.4" | 0" | ❄️ Dormant |
| Dec | — | 1.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Monroe 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 — Monroe County, MO
Tomatoes Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 17 | Feb 17 – Mar 3 |
| Transplant Outdoors | April 28 | Apr 28 – May 12 |
| Direct Sow | April 21 | Apr 21 – May 12 |
| Harvest | June 30 | Jun 30 – Sep 8 |
Plant 0.5" deep · 24" apart · Rows 36" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| 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 | — |
| 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: acceptable
🗺️ USDA Zone
Zone 5b
📆 Growing Season
190 days in Monroe County
Growing Tips for Tomatoes in Monroe County
Direct sow Tomatoes outdoors after April 14 in Monroe 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 Monroe County, MO?
Monroe County is in Zone 5b with an average last frost of April 14. Plan your Tomatoes planting based on this frost date — see the calendar above for exact timing.
What planting zone is Monroe County, MO?
Monroe County, Missouri is in USDA Hardiness Zone 5b. The average last spring frost is April 14 and first fall frost is October 21.
Plan Your Garden with Confidence
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