When to Plant Onion in St. Martin Parish, LA
St. Martin Parish, Louisiana gardeners: here's your May plan
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.
-
It's harvest week for onion
Check every 1–2 days. Many of these get tough or go to seed if you wait too long.
June prep starts now
- First harvests: onion
Onions are a fundamental kitchen staple available in yellow, white, and red varieties. Choose long-day, short-day, or intermediate types based on your latitude.
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 96°F, so Onion may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Onion will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Onion root diseases.
St. Martin Parish Soil Profile
Soil Type
Sandy Loam
Soil pH
5.2-6
Drainage
Well Drained
Plant Planting Risk Windows
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. Martin Parish
How your county's soil matches Onion's growing requirements.
Soil pH
Your soil pH (5.2–6.0) is more acidic than Onion prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
Sandy soil in St. Martin Parish warms quickly in spring but drains fast. Onion will need more frequent watering and regular compost additions to retain nutrients.
Drainage
Drainage is adequate for Onion.
Organic Matter
Organic matter is moderate (2.3%). Annual compost additions will help Onion.
How to Plant Onion
Fall planting: Sow 8 weeks before your first frost date for a fall harvest.
Plant Water Budget
Monthly Watering Guide for Onion
Onion needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Onion Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 5.1" | 0" | ❄️ Dormant |
| Feb | 4.3" | 4.4" | 0" | ✅ Rainfall sufficient |
| Mar | 4.3" | 5.7" | 0" | ✅ Rainfall sufficient |
| Apr | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| May | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| Jun | 4.3" | 5.1" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 6.4" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 5.6" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| Oct | 4.3" | 3.3" | 1" | 💧 Light watering |
| Nov | 4.3" | 4.4" | 0" | ✅ Rainfall sufficient |
| Dec | 4.3" | 4.1" | 0.2" | 💧 Light watering |
Water needs are for active growing months only (Feb–Dec in St. Martin Parish). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Onion 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.
Onion Planting Timeline — St. Martin Parish, LA
Onion Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 16 | Jan 16 – Jan 30 |
| Transplant Outdoors | February 13 | Feb 13 – Feb 27 |
| Direct Sow | January 23 | Jan 23 – Feb 13 |
| Harvest | May 15 | May 15 – Jul 3 |
| Fall Sowing | October 10 | Oct 10 – Oct 24 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors Direct Sow |
| February | Transplant Outdoors Direct Sow |
| March | — |
| April | — |
| May | Harvest |
| June | Harvest |
| July | Harvest |
| August | — |
| September | — |
| October | Fall Sowing |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Natural rainfall sufficient
📅 Days to Maturity
90–120 days
🧪 Soil pH
Needs 6–7 · Your soil: too_acidic
🗺️ USDA Zone
Zone 9a
📆 Growing Season
295 days in St. Martin Parish
Growing Tips for Onion in St. Martin Parish
Direct sow Onion outdoors after February 13 in St. Martin Parish when soil has warmed and frost danger has passed.
Sandy soil in St. Martin Parish dries quickly — mulch Onion 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. Martin Parish, provide afternoon shade for Onion and water deeply in the morning.
Common pests for Onion in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.
General growing tips
Start seeds indoors 8-10 weeks before transplanting. Match day-length type to your latitude. Stop watering when tops begin to fall over and cure bulbs for 2-3 weeks before storage.
Companion Planting
Good Companions
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Onion in Other Locations
Frequently Asked Questions
When should I plant Onion in St. Martin Parish, LA?
St. Martin Parish is in Zone 9a with an average last frost of February 13. Plan your Onion planting based on this frost date — 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.
Your St. Martin Parish Garden Planner — Free
A 24-page printable planner built for St. Martin 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.