When to Plant Cilantro in St. Helena Parish, LA
Your May game plan for St. Helena Parish, Louisiana
Welcome to May in Zone 9a. These are the moves that will have the biggest impact on your growing season.
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Pick cilantro
The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.
Get ahead of June
- First harvests: cilantro
Cilantro is a dual-purpose herb providing fresh leaves (cilantro) and dried seeds (coriander). It bolts quickly in heat, producing flowers beloved by beneficial insects.
St. Helena Parish, Louisiana is in USDA Zone 9a. The average last spring frost is March 5 and the first fall frost is November 30, giving you a growing season of approximately 270 days.
At an elevation of 437 feet, St. Helena Parish receives approximately 50 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 96°F, so Cilantro may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Cilantro will need more frequent watering and organic matter to retain nutrients.
St. Helena Parish Soil Profile
Soil Type
Sandy Loam
Soil pH
4.8-6.5
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. Helena Parish
How your county's soil matches Cilantro's growing requirements.
Soil pH
Your soil pH (4.8–6.5) is more acidic than Cilantro prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
Sandy soil in St. Helena Parish warms quickly in spring but drains fast. Cilantro will need more frequent watering and regular compost additions to retain nutrients.
Organic Matter
Organic matter is low (1.7%). Add 2-3 inches of compost before planting Cilantro.
How to Plant Cilantro
Fall planting: Sow 8 weeks before your first frost date for a fall harvest.
Succession Planting Cilantro
Sow every 4.6 weeks. Last sowing by Oct 01 to harvest before frost.
For a dedicated fall crop, sow by Oct 05.
Plant Water Budget
Monthly Watering Guide for Cilantro
Cilantro needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.
| Month | Cilantro Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 3.8" | 0" | ❄️ Dormant |
| Feb | — | 3.7" | 0" | ❄️ Dormant |
| Mar | 2.2" | 5.5" | 0" | ✅ Rainfall sufficient |
| Apr | 2.2" | 3.3" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 3.6" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 4.9" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 4.7" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 5.1" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 3.6" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 3.3" | 0" | ✅ Rainfall sufficient |
| Nov | 2.2" | 4.4" | 0" | ✅ Rainfall sufficient |
| Dec | — | 4" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in St. Helena Parish). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Cilantro 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.
Cilantro Planting Timeline — St. Helena Parish, LA
Cilantro Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 5 | Feb 5 – Feb 19 |
| Transplant Outdoors | February 26 | Feb 26 – Mar 12 |
| Direct Sow | February 12 | Feb 12 – Mar 5 |
| Harvest | April 9 | Apr 9 – Jun 11 |
| Fall Sowing | October 5 | Oct 5 – Oct 19 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors Transplant Outdoors Direct Sow |
| March | Transplant Outdoors Direct Sow |
| April | Harvest |
| May | Harvest |
| June | Harvest |
| July | — |
| August | — |
| September | — |
| October | Fall Sowing |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
0.5"/week · Natural rainfall sufficient
📅 Days to Maturity
40–60 days
🧪 Soil pH
Needs 6–7 · Your soil: too_acidic
🗺️ USDA Zone
Zone 9a
📆 Growing Season
270 days in St. Helena Parish
Growing Tips for Cilantro in St. Helena Parish
Direct sow Cilantro outdoors after March 05 in St. Helena Parish when soil has warmed and frost danger has passed.
Sandy soil in St. Helena Parish dries quickly — mulch Cilantro with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.
Summer highs in St. Helena Parish reach 96°F — grow Cilantro as a spring or fall crop. Use shade cloth if planting in summer.
Your generous 270.0-day season in St. Helena Parish allows multiple plantings of Cilantro. Sow every 20.0 days for continuous harvest.
Common pests for Cilantro in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.
General growing tips
Succession sow every 2-3 weeks. Provide afternoon shade in warm weather. Harvest leaves before flowering or allow some plants to go to seed for coriander and self-sowing.
Companion Planting
Good Companions
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Check more plant combinations with our Companion Planting Checker →
Cilantro in Other Locations
Frequently Asked Questions
When should I plant Cilantro in St. Helena Parish, LA?
St. Helena Parish is in Zone 9a with an average last frost of March 5. Plan your Cilantro planting based on this frost date — see the calendar above for exact timing.
What planting zone is St. Helena Parish, LA?
St. Helena Parish, Louisiana is in USDA Hardiness Zone 9a. The average last spring frost is March 5 and first fall frost is November 30.
Your St. Helena Parish Garden Planner — Free
A 24-page printable planner built for St. Helena 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.