Blog

When to Plant Watermelon in Grant Parish, LA

Grant Parish, Louisiana Zone 9a May

What to do in May

Your garden in Grant Parish, Louisiana is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost March 3
Avg. first frost November 19
Soil temp (4") 73°F
Watering Low
Pest pressure High
Daylight 13.6 hrs
  1. Collect watermelon at their peak

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

Get ahead of June
  • First harvests: watermelon

Instant PDF download. No spam, unsubscribe any time.

Watermelon is a sprawling vine crop that produces sweet, juicy fruits in hot weather. Varieties range from personal-sized icebox types to 50-pound giants.

Grant Parish, Louisiana is in USDA Zone 9a. The average last spring frost is March 3 and the first fall frost is November 19, giving you a growing season of approximately 261 days.

At an elevation of 356 feet, Grant Parish receives approximately 56.8 inches of rainfall annually with predominantly loam soil. Summer highs average 92°F, providing good warmth for Watermelon during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Watermelon root diseases.

Grant Parish, LA (Zone 9a) Long season
261 days
Last Spring Frost March 3
261 growing days
First Fall Frost November 19

Grant Parish Soil Profile

Soil Type

Loam

Soil pH

6.1-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (139 days to spare)
Start indoors: Jan 23 Transplant: Feb 27 🍅 Harvest: May 8 – Jun 26
Recommended (50%) ✓ Fits season (135 days to spare)
Start indoors: Feb 3 Transplant: Mar 10 🍅 Harvest: May 19 – Jul 7
Safe Start (90%) ✓ Fits season (139 days to spare)
Start indoors: Feb 24 Transplant: Mar 31 🍅 Harvest: Jun 9 – Jul 28

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 Grant Parish

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

Soil pH

Your soil pH (6.1–7.3) is within Watermelon's preferred range (6.0–7.5).

Soil Texture

The loam soil in Grant Parish is excellent for Watermelon — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.8%). Annual compost additions will help Watermelon.

How to Plant Watermelon

1"
Planting Depth
30"
Between Plants
42"
Between Rows

Succession Planting Watermelon

4
successive plantings in your 261-day season

Sow every 8 weeks. Last sowing by Aug 11 to harvest before frost.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.9″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 1,361 gal / 100 sq ft

Monthly Watering Guide for Watermelon

Watermelon needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Watermelon Needs Rainfall You Supplement Action
Jan 5" 0" ❄️ Dormant
Feb 4.2" 0" ❄️ Dormant
Mar 6.5" 6" 0.5" 💧 Light watering
Apr 6.5" 4.7" 1.8" 💧 Light watering
May 6.5" 4.8" 1.7" 💧 Light watering
Jun 6.5" 4.6" 1.9" 💧 Light watering
Jul 6.5" 6" 0.5" 💧 Light watering
Aug 6.5" 4.9" 1.6" 💧 Light watering
Sep 6.5" 4.4" 2.1" 💧 Light watering
Oct 6.5" 3.5" 3" 💧 Light watering
Nov 6.5" 4.2" 2.3" 💧 Light watering
Dec 4.4" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Grant Parish). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Watermelon 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.

Watermelon needs ~1,615 GDD — county provides 4,959 GDD Excellent fit

Watermelon Planting Timeline — Grant Parish, LA

Watermelon Planting Calendar

Activity When Date Range
Start Indoors February 3 Feb 3 – Feb 17
Transplant Outdoors March 10 Mar 10 – Mar 24
Direct Sow March 3 Mar 3 – Mar 24
Harvest May 19 May 19 – Jul 7

Plant 1" deep · 30" apart · Rows 42" apart

Month-by-Month Timeline

MonthActivities
January
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

1.5"/week · 1-2 times/week

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 9a

📆 Growing Season

261 days in Grant Parish

Growing Tips for Watermelon in Grant Parish

Direct sow Watermelon outdoors after March 03 in Grant Parish when soil has warmed and frost danger has passed.

Common pests for Watermelon in this region include squash vine borer and cucumber beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 3-4 weeks early or direct sow after soil is warm. Plant on mounds with plenty of space. Check ripeness by looking for a yellow ground spot and dull thump when tapped.

Recommended Watermelon Varieties for Grant Parish

Full-size melons that thrive with your long season

Crimson Sweet (85d) Charleston Gray (85d) Moon and Stars (95d)

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Watermelon in Grant Parish, LA?

Grant Parish is in Zone 9a with an average last frost of March 3. Plan your Watermelon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Grant Parish, LA?

Grant Parish, Louisiana is in USDA Hardiness Zone 9a. The average last spring frost is March 3 and first fall frost is November 19.

🌱

Your Grant Parish Garden Planner — Free

A 24-page printable planner built for Grant Parish (Zone 9a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Grant Parish, LA. 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.