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When to Plant Microgreens in St. Tammany Parish, LA

St. Tammany Parish, Louisiana Zone 9a May

Your May gardening checklist

Here's what deserves your attention in St. Tammany Parish, Louisiana this month. Everything below is tailored to Zone 9a and timed around your local frost dates.

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

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Microgreens are young seedlings of vegetables and herbs harvested at the cotyledon or first true leaf stage. They pack concentrated flavors and nutrients in a tiny package.

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 Microgreens may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Microgreens will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Microgreens 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

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 (254 days to spare)
Start indoors: Jan 2 Transplant: Jan 30 🍅 Harvest: Feb 6 – Mar 6
Recommended (50%) ✓ Fits season (241 days to spare)
Start indoors: Jan 23 Transplant: Feb 20 🍅 Harvest: Feb 27 – Mar 27
Safe Start (90%) ✓ Fits season (228 days to spare)
Start indoors: Mar 2 Transplant: Mar 30 🍅 Harvest: Apr 6 – May 4

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 Microgreens's growing requirements.

Soil pH

Your soil pH (4.8–6.1) is more acidic than Microgreens prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Microgreens.

Organic Matter

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

How to Plant Microgreens

0.5"
Planting Depth
2"
Between Plants
6"
Between Rows

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Succession Planting Microgreens

54
successive plantings in your 276-day season

Sow every 0.7 weeks. Last sowing by Nov 02 to harvest before frost.

For a dedicated fall crop, sow by Sep 28.

Plant Water Budget

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

Monthly Watering Guide for Microgreens

Microgreens needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Microgreens Needs Rainfall You Supplement Action
Jan 4.5" 0" ❄️ Dormant
Feb 4.3" 4.5" 0" ✅ Rainfall sufficient
Mar 4.3" 5.8" 0" ✅ Rainfall sufficient
Apr 4.3" 4.2" 0.1" 💧 Light watering
May 4.3" 5.2" 0" ✅ Rainfall sufficient
Jun 4.3" 4.6" 0" ✅ Rainfall sufficient
Jul 4.3" 6.8" 0" ✅ Rainfall sufficient
Aug 4.3" 5.3" 0" ✅ Rainfall sufficient
Sep 4.3" 4.2" 0.1" 💧 Light watering
Oct 4.3" 4.1" 0.2" 💧 Light watering
Nov 4.3" 4.3" 0" ✅ Rainfall sufficient
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.

Microgreens 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.

Microgreens needs ~308 GDD — county provides 6,094 GDD Excellent fit

Microgreens Planting Timeline — St. Tammany Parish, LA

Microgreens Planting Calendar

Activity When Date Range
Start Indoors January 23 Jan 23 – Feb 6
Transplant Outdoors February 20 Feb 20 – Mar 6
Direct Sow January 30 Jan 30 – Feb 20
Harvest February 27 Feb 27 – Mar 27
Fall Sowing September 28 Sep 28 – Oct 12

Plant 0.5" deep · 2" apart · Rows 6" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

7–21 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 9a

📆 Growing Season

276 days in St. Tammany Parish

Growing Tips for Microgreens in St. Tammany Parish

Direct sow Microgreens 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 Microgreens 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 Microgreens and water deeply in the morning.

Your generous 277.0-day season in St. Tammany Parish allows multiple plantings of Microgreens. Sow every 3.0 days for continuous harvest.

General growing tips

Sow seeds densely on shallow trays of moist growing medium. Cover until germination, then provide light. Harvest with scissors when 1-3 inches tall. Grow year-round indoors.

Frequently Asked Questions

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

St. Tammany Parish is in Zone 9a with an average last frost of February 20. Plan your Microgreens 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.