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When to Plant Asparagus in St. Mary Parish, LA

St. Mary Parish, Louisiana Zone 9b May

Top priorities for St. Mary Parish, Louisiana gardeners in May

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 14
Avg. first frost December 5
Soil temp (4") 77°F
Watering Low
Pest pressure High
Daylight 13.5 hrs

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Asparagus is a long-lived perennial vegetable that produces tender spears each spring for 15-20 years once established. It requires patience but rewards with reliable harvests.

St. Mary Parish, Louisiana is in USDA Zone 9b. The average last spring frost is February 14 and the first fall frost is December 5, giving you a growing season of approximately 294 days.

At an elevation of 252 feet, St. Mary Parish receives approximately 48.5 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 95°F, so Asparagus may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Asparagus will need more frequent watering and organic matter to retain nutrients.

St. Mary Parish, LA (Zone 9b) Year-round
294 days
Last Spring Frost February 14
294 growing days
First Fall Frost December 5
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St. Mary Parish Soil Profile

Soil Type

Sandy Loam

Soil pH

4.8-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: Feb 19
Recommended (50%) ✓ Fits season
Transplant: Feb 28
Safe Start (90%) ✓ Fits season
Transplant: Mar 25

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. Mary Parish

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

Soil pH

Your soil pH (4.8–6.4) is more acidic than Asparagus prefers (6.5–7.5). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Asparagus.

Organic Matter

Organic matter is moderate (2.0%). Annual compost additions will help Asparagus.

How to Plant Asparagus

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

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.7″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Asparagus

Asparagus needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.

Month Asparagus Needs Rainfall You Supplement Action
Jan 3.6" 0" ❄️ Dormant
Feb 3.5" 3.4" 0.1" 💧 Light watering
Mar 3.5" 5.1" 0" ✅ Rainfall sufficient
Apr 3.5" 3.8" 0" ✅ Rainfall sufficient
May 3.5" 3.8" 0" ✅ Rainfall sufficient
Jun 3.5" 3.6" 0" ✅ Rainfall sufficient
Jul 3.5" 5.6" 0" ✅ Rainfall sufficient
Aug 3.5" 5.1" 0" ✅ Rainfall sufficient
Sep 3.5" 3.5" 0" ✅ Rainfall sufficient
Oct 3.5" 3.1" 0.4" 💧 Light watering
Nov 3.5" 3.9" 0" ✅ Rainfall sufficient
Dec 3.5" 4.2" 0" ✅ Rainfall sufficient

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

Asparagus 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.

Asparagus needs ~19,391 GDD — county provides 6,268 GDD May not mature

Asparagus Planting Timeline — St. Mary Parish, LA

Asparagus Planting Calendar

Activity When Date Range
Transplant Outdoors February 28 Feb 28 – Mar 14

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

Month-by-Month Timeline

MonthActivities
January
February Transplant Outdoors
March Transplant Outdoors
April
May
June
July
August
September
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · Natural rainfall sufficient

📅 Days to Maturity

730–1095 days

🧪 Soil pH

Needs 6.5–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 9b

📆 Growing Season

294 days in St. Mary Parish

Growing Tips for Asparagus in St. Mary Parish

Direct sow Asparagus outdoors after February 14 in St. Mary Parish when soil has warmed and frost danger has passed.

Sandy soil in St. Mary Parish dries quickly — mulch Asparagus with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

Your 295.0-day growing season in St. Mary Parish is tight for Asparagus (730.0-1095.0 days to maturity). Start indoors and choose early-maturing varieties.

General growing tips

Plant crowns in deep trenches with compost. Do not harvest spears for the first two years to allow root establishment. Mulch heavily to suppress weeds and retain moisture.

Companion Planting

Good Companions

Avoid Planting Near

  • Garlic
  • Onion

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Asparagus in St. Mary Parish, LA?

St. Mary Parish is in Zone 9b with an average last frost of February 14. Plan your Asparagus planting based on this frost date — see the calendar above for exact timing.

What planting zone is St. Mary Parish, LA?

St. Mary Parish, Louisiana is in USDA Hardiness Zone 9b. The average last spring frost is February 14 and first fall frost is December 5.

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Your St. Mary Parish Garden Planner — Free

A 24-page printable planner built for St. Mary Parish (Zone 9b). 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. Mary 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.