When to Plant Tomatoes in Union County, MS
May in the garden — Union County, Mississippi
We've pulled the most time-sensitive tasks for Union County, Mississippi this May and put them front and centre. Tackle them in order.
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Indoor seed-starting week for tomatoes
You're about 25 weeks out from your last frost — the perfect window to get these germinating indoors.
To set up a strong June, 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.
Union County, Mississippi is in USDA Zone 8a. The average last spring frost is March 30 and the first fall frost is October 29, giving you a growing season of approximately 213 days.
At an elevation of 196 feet, Union County receives approximately 49.9 inches of rainfall annually with predominantly clay loam soil. Summer highs average 94°F, providing good warmth for Tomatoes during the growing season. Clay soil retains moisture well for Tomatoes, but amend with compost to improve drainage and prevent root rot.
Union County Soil Profile
Soil Type
Clay Loam
Soil pH
5.3-6.8
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 Union County
How your county's soil matches Tomatoes's growing requirements.
Soil pH
Your soil pH (5.3–6.8) overlaps with Tomatoes's range (6.0–7.0), though not a perfect match.
Soil Texture
The clay loam soil in Union County is excellent for Tomatoes — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.3%). Annual compost additions will help Tomatoes.
How to Plant Tomatoes
Succession Planting Tomatoes
Sow every 6.9 weeks. Last sowing by Aug 05 to harvest before frost.
Plant Water Budget
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 | — | 3.8" | 0" | ❄️ Dormant |
| Feb | — | 3.8" | 0" | ❄️ Dormant |
| Mar | 5.2" | 5.2" | 0" | ✅ Rainfall sufficient |
| Apr | 5.2" | 3.6" | 1.6" | 💧 Light watering |
| May | 5.2" | 4.6" | 0.6" | 💧 Light watering |
| Jun | 5.2" | 4.8" | 0.4" | 💧 Light watering |
| Jul | 5.2" | 5.1" | 0.1" | 💧 Light watering |
| Aug | 5.2" | 4.6" | 0.6" | 💧 Light watering |
| Sep | 5.2" | 3.4" | 1.8" | 💧 Light watering |
| Oct | 5.2" | 3.2" | 2" | 💧 Light watering |
| Nov | — | 3.6" | 0" | ❄️ Dormant |
| Dec | — | 4.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Oct in Union 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 — Union County, MS
Tomatoes Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 9 | Feb 9 – Feb 23 |
| Transplant Outdoors | April 13 | Apr 13 – Apr 27 |
| Direct Sow | April 6 | Apr 6 – Apr 27 |
| Harvest | June 15 | Jun 15 – Aug 24 |
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 | — |
| June | Harvest |
| July | Harvest |
| August | Harvest |
| September | — |
| 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 8a
📆 Growing Season
213 days in Union County
Growing Tips for Tomatoes in Union County
Direct sow Tomatoes outdoors after March 30 in Union County when soil has warmed and frost danger has passed.
With Union County's clay soil (29% clay), work in 3-4 inches of compost before planting Tomatoes. Avoid tilling when soil is wet to prevent compaction.
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 Union County, MS?
Union County is in Zone 8a with an average last frost of March 30. Plan your Tomatoes planting based on this frost date — see the calendar above for exact timing.
What planting zone is Union County, MS?
Union County, Mississippi is in USDA Hardiness Zone 8a. The average last spring frost is March 30 and first fall frost is October 29.
Your Union County Garden Planner — Free
A 24-page printable planner built for Union County (Zone 8a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.