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When to Plant Turmeric in Coos County, OR

Coos County, Oregon Zone 9a May

Your May gardening checklist

Your Coos County, Oregon garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost March 22
Avg. first frost November 19
Soil temp (4") 71°F
Watering High
Pest pressure High
Daylight 14.5 hrs
  1. Sow turmeric in trays indoors

    You're about 25 weeks out from your last frost — the perfect window to get these germinating indoors.

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Turmeric is a tropical plant producing bright orange rhizomes with a warm, earthy flavor and potent anti-inflammatory properties. It is closely related to ginger.

Coos County, Oregon is in USDA Zone 9a. The average last spring frost is March 22 and the first fall frost is November 19, giving you a growing season of approximately 242 days.

At an elevation of 96 feet, Coos County receives approximately 38.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Turmeric during the growing season.

Coos County, OR (Zone 9a) Long season
242 days
Last Spring Frost March 22
242 growing days
First Fall Frost November 19
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Coos County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (296 days to spare)
Start indoors: Jan 24 Transplant: Mar 14 🍅 Harvest: Nov 14 – Jan 9
Recommended (50%) ✓ Fits season (299 days to spare)
Start indoors: Feb 8 Transplant: Mar 29 🍅 Harvest: Nov 29 – Jan 24
Safe Start (90%) ✓ Fits season (294 days to spare)
Start indoors: Mar 11 Transplant: Apr 29 🍅 Harvest: Dec 30 – Feb 24

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 Coos County

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

Soil pH

Your soil pH (5.4–6.8) overlaps with Turmeric's range (5.5–7.5), though not a perfect match.

Soil Texture

The silt loam soil in Coos County is excellent for Turmeric — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.7%) — Turmeric will thrive.

How to Plant Turmeric

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.7″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 1,780 gal / 100 sq ft

Monthly Watering Guide for Turmeric

Turmeric needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Turmeric Needs Rainfall You Supplement Action
Jan 5.5" 0" ❄️ Dormant
Feb 4.5" 0" ❄️ Dormant
Mar 6.5" 4.4" 2.1" 💧 Light watering
Apr 6.5" 3.1" 3.4" 🚿 Regular watering
May 6.5" 2.3" 4.2" 🚿 Regular watering
Jun 6.5" 1.6" 4.9" 🚿 Regular watering
Jul 6.5" 0.6" 5.9" 🚿 Regular watering
Aug 6.5" 0.8" 5.7" 🚿 Regular watering
Sep 6.5" 1.4" 5.1" 🚿 Regular watering
Oct 6.5" 3.3" 3.2" 💧 Light watering
Nov 6.5" 5.9" 0.6" 💧 Light watering
Dec 5.5" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Coos County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Turmeric 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.

Turmeric needs ~4,522 GDD — county provides 4,053 GDD May not mature

Turmeric Planting Timeline — Coos County, OR

Turmeric Planting Calendar

Activity When Date Range
Start Indoors February 8 Feb 8 – Feb 22
Transplant Outdoors March 29 Mar 29 – Apr 12
Direct Sow March 22 Mar 22 – Apr 12
Harvest November 29 Nov 29 – Jan 24

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1.5"/week · 2-3 times/week

📅 Days to Maturity

240–300 days

🧪 Soil pH

Needs 5.5–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

242 days in Coos County

Growing Tips for Turmeric in Coos County

Direct sow Turmeric outdoors after March 22 in Coos County when soil has warmed and frost danger has passed.

Your 242.0-day growing season in Coos County is tight for Turmeric (240.0-300.0 days to maturity). Start indoors and choose early-maturing varieties.

General growing tips

Plant rhizome pieces 2 inches deep in rich, moist soil after last frost. Maintain warmth and humidity. Harvest after foliage dies back in fall. In cold climates, grow in large containers.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Turmeric in Coos County, OR?

Coos County is in Zone 9a with an average last frost of March 22. Plan your Turmeric planting based on this frost date — see the calendar above for exact timing.

What planting zone is Coos County, OR?

Coos County, Oregon is in USDA Hardiness Zone 9a. The average last spring frost is March 22 and first fall frost is November 19.

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Your Coos County Garden Planner — Free

A 24-page printable planner built for Coos County (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 Coos County, OR. 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.