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When to Plant Tomatoes in Harrison County, MS

Harrison County, Mississippi Zone 9a May

What to do in May

Your garden in Harrison County, Mississippi is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost March 4
Avg. first frost November 26
Soil temp (4") 72°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. Collect tomatoes at their peak

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

Before June arrives, get these ready
  • 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.

Harrison County, Mississippi is in USDA Zone 9a. The average last spring frost is March 4 and the first fall frost is November 26, giving you a growing season of approximately 267 days.

At an elevation of 190 feet, Harrison County receives approximately 53 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 96°F, so Tomatoes may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Tomatoes will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Tomatoes root diseases.

Harrison County, MS (Zone 9a) Long season
267 days
Last Spring Frost March 4
267 growing days
First Fall Frost November 26

Harrison County Soil Profile

Soil Type

Sandy Loam

Soil pH

4.8-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (131 days to spare)
Start indoors: Jan 7 Transplant: Feb 25 🍅 Harvest: Apr 29 – Jul 8
Recommended (50%) ✓ Fits season (127 days to spare)
Start indoors: Jan 21 Transplant: Mar 11 🍅 Harvest: May 13 – Jul 22
Safe Start (90%) ✓ Fits season (126 days to spare)
Start indoors: Feb 12 Transplant: Apr 2 🍅 Harvest: Jun 4 – Aug 13

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 Harrison County

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

Soil pH

Your soil pH (4.8–6.2) is more acidic than Tomatoes prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

Sandy soil in Harrison County warms quickly in spring but drains fast. Tomatoes will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Tomatoes.

Organic Matter

Organic matter is moderate (2.1%). 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 267-day season

Sow every 6.9 weeks. Last sowing by Sep 02 to harvest before frost.

Plant Water Budget

Plant needs
1.2″/week
Rainfall provides
0.8″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 18 gal / 100 sq ft
Drought risk

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 4.1" 0" ❄️ Dormant
Feb 4.1" 0" ❄️ Dormant
Mar 5.2" 4.9" 0.3" 💧 Light watering
Apr 5.2" 3.8" 1.4" 💧 Light watering
May 5.2" 4.1" 1.1" 💧 Light watering
Jun 5.2" 4.9" 0.3" 💧 Light watering
Jul 5.2" 6.3" 0" ✅ Rainfall sufficient
Aug 5.2" 4.5" 0.7" 💧 Light watering
Sep 5.2" 4.2" 1" 💧 Light watering
Oct 5.2" 3.6" 1.6" 💧 Light watering
Nov 5.2" 4.3" 0.9" 💧 Light watering
Dec 4.3" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Harrison 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 ~1,595 GDD — county provides 5,874 GDD Excellent fit

Tomatoes Planting Timeline — Harrison County, MS

Tomatoes Planting Calendar

Activity When Date Range
Start Indoors January 21 Jan 21 – Feb 4
Transplant Outdoors March 11 Mar 11 – Mar 25
Direct Sow March 4 Mar 4 – Mar 25
Harvest May 13 May 13 – Jul 22

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

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Start Indoors
March Transplant Outdoors Direct Sow
April
May Harvest
June Harvest
July Harvest
August
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: too_acidic

🗺️ USDA Zone

Zone 9a

📆 Growing Season

267 days in Harrison County

Growing Tips for Tomatoes in Harrison County

Direct sow Tomatoes outdoors after March 04 in Harrison County when soil has warmed and frost danger has passed.

Sandy soil in Harrison County dries quickly — mulch Tomatoes with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 96°F in Harrison County, provide afternoon shade for Tomatoes and water deeply in the morning.

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 Harrison County

Heat-set varieties that pollinate reliably above 90°F

Solar Fire Florida 91 Phoenix Heat Wave II

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 Harrison County, MS?

Harrison County is in Zone 9a with an average last frost of March 4. Plan your Tomatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Harrison County, MS?

Harrison County, Mississippi is in USDA Hardiness Zone 9a. The average last spring frost is March 4 and first fall frost is November 26.

🌱

Your Harrison County Garden Planner — Free

A 24-page printable planner built for Harrison County (Zone 9a). 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 Harrison 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.