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When to Plant Tomatoes in Lamar County, MS

Lamar County, Mississippi Zone 8b May

Top priorities for Lamar County, Mississippi gardeners in May

Welcome to May in Zone 8b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost March 6
Avg. first frost November 21
Soil temp (4") 71°F
Watering Moderate
Pest pressure High
Daylight 13.6 hrs
  1. Harvest tomatoes as they ripen

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

A few tasks this May that'll pay off in June
  • First harvests: tomatoes

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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.

Lamar County, Mississippi is in USDA Zone 8b. The average last spring frost is March 6 and the first fall frost is November 21, giving you a growing season of approximately 260 days.

At an elevation of 62 feet, Lamar County receives approximately 51.6 inches of rainfall annually with predominantly clay loam soil. Summer highs average 91°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. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Tomatoes root diseases.

Lamar County, MS (Zone 8b) Long season
260 days
Last Spring Frost March 6
260 growing days
First Fall Frost November 21

Lamar County Soil Profile

Soil Type

Clay Loam

Soil pH

5.8-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (112 days to spare)
Start indoors: Jan 10 Transplant: Mar 14 🍅 Harvest: May 16 – Jul 25
Recommended (50%) ✓ Fits season (113 days to spare)
Start indoors: Jan 16 Transplant: Mar 20 🍅 Harvest: May 22 – Jul 31
Safe Start (90%) ✓ Fits season (109 days to spare)
Start indoors: Feb 5 Transplant: Apr 9 🍅 Harvest: Jun 11 – Aug 20

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 Lamar County

How your county's soil matches Tomatoes's growing requirements.

Soil pH

Your soil pH (5.8–6.4) overlaps with Tomatoes's range (6.0–7.0), though not a perfect match.

Soil Texture

The clay loam soil in Lamar County is excellent for Tomatoes — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.2%). Annual compost additions will help Tomatoes.

How to Plant Tomatoes

0.5"
Planting Depth
24"
Between Plants
36"
Between Rows

Succession Planting Tomatoes

5
successive plantings in your 260-day season

Sow every 6.9 weeks. Last sowing by Aug 28 to harvest before frost.

Plant Water Budget

Plant needs
1.2″/week
Rainfall provides
0.8″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 848 gal / 100 sq ft

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 4.9" 0" ❄️ Dormant
Feb 3.7" 0" ❄️ Dormant
Mar 5.2" 4.9" 0.3" 💧 Light watering
Apr 5.2" 4.2" 1" 💧 Light watering
May 5.2" 3.5" 1.7" 💧 Light watering
Jun 5.2" 4.2" 1" 💧 Light watering
Jul 5.2" 6" 0" ✅ Rainfall sufficient
Aug 5.2" 5.4" 0" ✅ Rainfall sufficient
Sep 5.2" 4.2" 1" 💧 Light watering
Oct 5.2" 3.7" 1.5" 💧 Light watering
Nov 5.2" 3.4" 1.8" 💧 Light watering
Dec 3.7" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Lamar 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 needs ~1,323 GDD — county provides 4,745 GDD Excellent fit

Tomatoes Planting Timeline — Lamar County, MS

Tomatoes Planting Calendar

Activity When Date Range
Start Indoors January 16 Jan 16 – Jan 30
Transplant Outdoors March 20 Mar 20 – Apr 3
Direct Sow March 13 Mar 13 – Apr 3
Harvest May 22 May 22 – Jul 31

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

Month-by-Month Timeline

MonthActivities
January Start Indoors
February
March Transplant Outdoors Direct Sow
April Transplant Outdoors Direct Sow
May Harvest
June Harvest
July Harvest
August
September
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 8b

📆 Growing Season

260 days in Lamar County

Growing Tips for Tomatoes in Lamar County

Direct sow Tomatoes outdoors after March 06 in Lamar County when soil has warmed and frost danger has passed.

With Lamar County's clay soil (27% 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.

Recommended Tomatoes Varieties for Lamar County

Your long season supports large indeterminate heirloom types

Brandywine (80d) Cherokee Purple (80d) San Marzano (80d) Mortgage Lifter (85d)

Disease-resistant varieties for your humid climate

Mountain Merit (VF) Defiant (LB) Iron Lady (EB/LB/SF)

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 Lamar County, MS?

Lamar County is in Zone 8b with an average last frost of March 6. Plan your Tomatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lamar County, MS?

Lamar County, Mississippi is in USDA Hardiness Zone 8b. The average last spring frost is March 6 and first fall frost is November 21.

🌱

Your Lamar County Garden Planner — Free

A 24-page printable planner built for Lamar County (Zone 8b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Lamar County, MS. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.