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When to Plant Zucchini in St. Tammany Parish, LA

St. Tammany Parish, Louisiana Zone 9a May

May in St. Tammany Parish, Louisiana — your action list

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost February 20
Avg. first frost November 23
Soil temp (4") 74°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. Basket week: zucchini

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  • First harvests: zucchini

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Zucchini is an incredibly prolific summer squash that can produce an abundance of fruit from just a few plants. It is versatile in the kitchen from grilling to baking.

St. Tammany Parish, Louisiana is in USDA Zone 9a. The average last spring frost is February 20 and the first fall frost is November 23, giving you a growing season of approximately 276 days.

At an elevation of 321 feet, St. Tammany Parish receives approximately 57.9 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 96°F, so Zucchini may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Zucchini will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Zucchini root diseases.

St. Tammany Parish, LA (Zone 9a) Year-round
276 days
Last Spring Frost February 20
276 growing days
First Fall Frost November 23
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St. Tammany Parish Soil Profile

Soil Type

Sandy Loam

Soil pH

4.8-6.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (177 days to spare)
Start indoors: Jan 2 Transplant: Feb 6 🍅 Harvest: Mar 27 – May 22
Recommended (50%) ✓ Fits season (164 days to spare)
Start indoors: Jan 23 Transplant: Feb 27 🍅 Harvest: Apr 17 – Jun 12
Safe Start (90%) ✓ Fits season (151 days to spare)
Start indoors: Mar 2 Transplant: Apr 6 🍅 Harvest: May 25 – Jul 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 St. Tammany Parish

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

Soil pH

Your soil pH (4.8–6.1) is more acidic than Zucchini prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

Sandy soil in St. Tammany Parish warms quickly in spring but drains fast. Zucchini will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Zucchini.

Organic Matter

Organic matter is moderate (2.1%). Annual compost additions will help Zucchini.

How to Plant Zucchini

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

Succession Planting Zucchini

7
successive plantings in your 276-day season

Sow every 5.1 weeks. Last sowing by Sep 24 to harvest before frost.

Plant Water Budget

Plant needs
1.2″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Zucchini

Zucchini 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 Zucchini Needs Rainfall You Supplement Action
Jan 4.5" 0" ❄️ Dormant
Feb 5.2" 4.5" 0.7" 💧 Light watering
Mar 5.2" 5.8" 0" ✅ Rainfall sufficient
Apr 5.2" 4.2" 1" 💧 Light watering
May 5.2" 5.2" 0" ✅ Rainfall sufficient
Jun 5.2" 4.6" 0.6" 💧 Light watering
Jul 5.2" 6.8" 0" ✅ Rainfall sufficient
Aug 5.2" 5.3" 0" ✅ Rainfall sufficient
Sep 5.2" 4.2" 1" 💧 Light watering
Oct 5.2" 4.1" 1.1" 💧 Light watering
Nov 5.2" 4.3" 0.9" 💧 Light watering
Dec 4.3" 0" ❄️ Dormant

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

Zucchini 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.

Zucchini needs ~1,155 GDD — county provides 6,094 GDD Excellent fit

Zucchini Planting Timeline — St. Tammany Parish, LA

Zucchini Planting Calendar

Activity When Date Range
Start Indoors January 23 Jan 23 – Feb 6
Transplant Outdoors February 27 Feb 27 – Mar 13
Direct Sow February 20 Feb 20 – Mar 13
Harvest April 17 Apr 17 – Jun 12

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.2"/week · Natural rainfall sufficient

📅 Days to Maturity

45–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 9a

📆 Growing Season

276 days in St. Tammany Parish

Growing Tips for Zucchini in St. Tammany Parish

Direct sow Zucchini outdoors after February 20 in St. Tammany Parish when soil has warmed and frost danger has passed.

Sandy soil in St. Tammany Parish dries quickly — mulch Zucchini 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 St. Tammany Parish, provide afternoon shade for Zucchini and water deeply in the morning.

Your generous 277.0-day season in St. Tammany Parish allows multiple plantings of Zucchini. Sow every 22.0 days for continuous harvest.

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

General growing tips

Direct sow after last frost. Harvest when fruits are 6-8 inches long for best flavor and texture. Check plants daily in summer as fruits can double in size overnight.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Zucchini in St. Tammany Parish, LA?

St. Tammany Parish is in Zone 9a with an average last frost of February 20. Plan your Zucchini planting based on this frost date — see the calendar above for exact timing.

What planting zone is St. Tammany Parish, LA?

St. Tammany Parish, Louisiana is in USDA Hardiness Zone 9a. The average last spring frost is February 20 and first fall frost is November 23.

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Your St. Tammany Parish Garden Planner — Free

A 24-page printable planner built for St. Tammany 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.

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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. Tammany 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.