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When to Plant Sorrel in Polk County, OR

Polk County, Oregon Zone 8b May

Your May game plan for Polk County, Oregon

We've pulled the most time-sensitive tasks for Polk County, Oregon this May and put them front and centre. Tackle them in order.

Avg. last frost April 10
Avg. first frost October 31
Soil temp (4") 72°F
Watering Moderate
Pest pressure High
Daylight 14.6 hrs
  1. Start sorrel indoors

    Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.

  2. Pick sorrel

    If you can't use it all right away, check the food-preservation section of your planner.

Get ahead of June
  • First harvests: sorrel

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Sorrel is a perennial herb with tangy, lemon-flavored arrow-shaped leaves. It is one of the first greens to emerge in spring and is used in soups and salads.

Polk County, Oregon is in USDA Zone 8b. The average last spring frost is April 10 and the first fall frost is October 31, giving you a growing season of approximately 204 days.

At an elevation of 331 feet, Polk County receives approximately 54.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81°F, so choose short-season varieties of Sorrel to ensure they mature before fall. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Sorrel root diseases.

Polk County, OR (Zone 8b) Long season
204 days
Last Spring Frost April 10
204 growing days
First Fall Frost October 31

Polk County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (117 days to spare)
Start indoors: Feb 17 Transplant: Mar 17 🍅 Harvest: Apr 28 – Jun 30
Recommended (50%) ✓ Fits season (106 days to spare)
Start indoors: Mar 6 Transplant: Apr 3 🍅 Harvest: May 15 – Jul 17
Safe Start (90%) ✓ Fits season (112 days to spare)
Start indoors: Mar 28 Transplant: Apr 25 🍅 Harvest: Jun 6 – Aug 8

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 Polk County

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

Soil pH

Your soil pH (5.7–6.5) is within Sorrel's preferred range (5.5–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.7%) — Sorrel will thrive.

How to Plant Sorrel

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Sorrel

6
successive plantings in your 204-day season

Sow every 4.6 weeks. Last sowing by Sep 01 to harvest before frost.

For a dedicated fall crop, sow by Aug 22.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Sorrel

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

Month Sorrel Needs Rainfall You Supplement Action
Jan 8.7" 0" ❄️ Dormant
Feb 5.6" 0" ❄️ Dormant
Mar 5" 0" ❄️ Dormant
Apr 4.3" 4.2" 0.1" 💧 Light watering
May 4.3" 3.5" 0.8" 💧 Light watering
Jun 4.3" 2.4" 1.9" 💧 Light watering
Jul 4.3" 0.9" 3.4" 🚿 Regular watering
Aug 4.3" 1.1" 3.2" 🚿 Regular watering
Sep 4.3" 1.8" 2.5" 🚿 Regular watering
Oct 4.3" 4.5" 0" ✅ Rainfall sufficient
Nov 8.1" 0" ❄️ Dormant
Dec 8.8" 0" ❄️ Dormant

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

Sorrel 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.

Sorrel needs ~538 GDD — county provides 2,193 GDD Excellent fit

Sorrel Planting Timeline — Polk County, OR

Sorrel Planting Calendar

Activity When Date Range
Start Indoors March 6 Mar 6 – Mar 20
Transplant Outdoors April 3 Apr 3 – Apr 17
Direct Sow March 27 Mar 27 – Apr 17
Harvest May 15 May 15 – Jul 17
Fall Sowing August 22 Aug 22 – Sep 5

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 5.5–7 · Your soil: ideal

🗺️ USDA Zone

Zone 8b

📆 Growing Season

204 days in Polk County

Growing Tips for Sorrel in Polk County

Direct sow Sorrel outdoors after April 10 in Polk County when soil has warmed and frost danger has passed.

Your generous 204.0-day season in Polk County allows multiple plantings of Sorrel. Sow every 20.0 days for continuous harvest.

General growing tips

Direct sow in early spring or fall. Remove flower stalks promptly to encourage leaf production. Divide clumps every 3-4 years. Young leaves have the best flavor.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sorrel in Polk County, OR?

Polk County is in Zone 8b with an average last frost of April 10. Plan your Sorrel planting based on this frost date — see the calendar above for exact timing.

What planting zone is Polk County, OR?

Polk County, Oregon is in USDA Hardiness Zone 8b. The average last spring frost is April 10 and first fall frost is October 31.

🌱

Your Polk County Garden Planner — Free

A 24-page printable planner built for Polk County (Zone 8b). 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 Polk 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.