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When to Plant Sunflower in St. Martin Parish, LA

Sunflowers are tall, cheerful annuals grown for their edible seeds and as pollinator magnets. They come in sizes from 2-foot dwarfs to 12-foot giants.

St. Martin Parish, Louisiana is in USDA Zone 9a. The average last spring frost is February 13 and the first fall frost is December 5, giving you a growing season of approximately 295 days.

At an elevation of 417 feet, St. Martin Parish receives approximately 55.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 96ยฐF, so Sunflower may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring โ€” great for early planting โ€” but Sunflower will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Sunflower root diseases.

St. Martin Parish, LA (Zone 9a) Year-round
295 days
Last Spring Frost February 13
295 growing days
First Fall Frost December 5

St. Martin Parish Soil Profile

Soil Type

Sandy Loam

Soil pH

5.2-6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (173 days to spare)
Start indoors: Dec 20 Transplant: Feb 7 🍅 Harvest: Apr 18 – Jun 6
Recommended (50%) ✓ Fits season (169 days to spare)
Start indoors: Jan 2 Transplant: Feb 20 🍅 Harvest: May 1 – Jun 19
Safe Start (90%) ✓ Fits season (159 days to spare)
Start indoors: Jan 26 Transplant: Mar 16 🍅 Harvest: May 25 – Jul 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.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Sunflower needs ~1,870 GDD — county provides 6,512 GDD Excellent fit

Sunflower Planting Timeline โ€” St. Martin Parish, LA

Sunflower Planting Calendar

Activity When Date Range
Start Indoors January 2 Jan 2 โ€“ Jan 16
Transplant Outdoors February 20 Feb 20 โ€“ Mar 6
Direct Sow February 13 Feb 13 โ€“ Mar 6
Harvest May 1 May 1 โ€“ Jun 19

Plant 1" deep ยท 18" apart ยท Rows 30" apart

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Transplant Outdoors Direct Sow
March Transplant Outdoors Direct Sow
April โ€”
May Harvest
June Harvest
July โ€”
August โ€”
September โ€”
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Low โ€” drought tolerant

Days to Maturity

70โ€“100 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 9a

Growing Season

295 days

Growing Tips for St. Martin Parish

Direct sow after last frost. Stake tall varieties in windy areas. Harvest seed heads when the back turns brown and seeds are plump. Dry heads upside down.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Level Up Your Garden

Frequently Asked Questions

When should I plant Sunflower in St. Martin Parish, LA?

St. Martin Parish is in Zone 9a with an average last frost of February 13. Plan your Sunflower planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is St. Martin Parish, LA?

St. Martin Parish, Louisiana is in USDA Hardiness Zone 9a. The average last spring frost is February 13 and first fall frost is December 5.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help St. Martin Parish gardeners in Zone 9a organize planting dates, track what's growing, and never miss a planting window.

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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 St. Martin Parish, LA. Local conditions may vary. Last updated: April 2026.