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When to Plant Sunchoke in St. John the Baptist Parish, LA

St. John the Baptist Parish, Louisiana Zone 9b May

May to-do list for St. John the Baptist Parish, Louisiana

May is a pivotal month for St. John the Baptist Parish, Louisiana gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost February 20
Avg. first frost December 1
Soil temp (4") 78°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
Coming up in June — start thinking about
  • First harvests: sunchoke

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Sunchokes (Jerusalem artichokes) are a native sunflower relative grown for their knobby, nutty-flavored tubers. They are extremely productive and nearly impossible to eradicate.

St. John the Baptist Parish, Louisiana is in USDA Zone 9b. The average last spring frost is February 20 and the first fall frost is December 1, giving you a growing season of approximately 284 days.

At an elevation of 309 feet, St. John the Baptist Parish receives approximately 53.7 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 103°F, so Sunchoke may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Sunchoke will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Sunchoke root diseases.

St. John the Baptist Parish, LA (Zone 9b) Year-round
284 days
Last Spring Frost February 20
284 growing days
First Fall Frost December 1
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St. John the Baptist 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 (106 days to spare)
Transplant: Feb 20 🍅 Harvest: Jun 12 – Aug 7
Recommended (50%) ✓ Fits season (102 days to spare)
Transplant: Mar 6 🍅 Harvest: Jun 26 – Aug 21
Safe Start (90%) ✓ Fits season (89 days to spare)
Transplant: Apr 5 🍅 Harvest: Jul 26 – Sep 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. John the Baptist Parish

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

Soil pH

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

Soil Texture

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

Drainage

Drainage is adequate for Sunchoke.

Organic Matter

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

How to Plant Sunchoke

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/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 Sunchoke

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

Month Sunchoke Needs Rainfall You Supplement Action
Jan 4" 0" ❄️ Dormant
Feb 4.3" 4" 0.3" 💧 Light watering
Mar 4.3" 4.6" 0" ✅ Rainfall sufficient
Apr 4.3" 4" 0.3" 💧 Light watering
May 4.3" 4.7" 0" ✅ Rainfall sufficient
Jun 4.3" 5" 0" ✅ Rainfall sufficient
Jul 4.3" 6.3" 0" ✅ Rainfall sufficient
Aug 4.3" 4.7" 0" ✅ Rainfall sufficient
Sep 4.3" 4.3" 0" ✅ Rainfall sufficient
Oct 4.3" 3.7" 0.6" 💧 Light watering
Nov 4.3" 3.5" 0.8" 💧 Light watering
Dec 4.3" 4.8" 0" ✅ Rainfall sufficient

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

Sunchoke 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.

Sunchoke needs ~3,542 GDD — county provides 7,766 GDD Excellent fit

Sunchoke Planting Timeline — St. John the Baptist Parish, LA

Sunchoke Planting Calendar

Activity When Date Range
Transplant Outdoors March 6 Mar 6 – Mar 20
Harvest June 26 Jun 26 – Aug 21

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

110–150 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 9b

📆 Growing Season

284 days in St. John the Baptist Parish

Growing Tips for Sunchoke in St. John the Baptist Parish

Direct sow Sunchoke outdoors after February 20 in St. John the Baptist Parish when soil has warmed and frost danger has passed.

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

With summer highs reaching 103°F in St. John the Baptist Parish, provide afternoon shade for Sunchoke and water deeply in the morning.

Common pests for Sunchoke in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Plant tubers 4 inches deep in early spring. Contain plants with barriers as they spread aggressively. Harvest after frost or leave in ground and dig as needed through winter.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sunchoke in St. John the Baptist Parish, LA?

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

What planting zone is St. John the Baptist Parish, LA?

St. John the Baptist Parish, Louisiana is in USDA Hardiness Zone 9b. The average last spring frost is February 20 and first fall frost is December 1.

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Your St. John the Baptist Parish Garden Planner — Free

A 24-page printable planner built for St. John the Baptist 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. John the Baptist 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.