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When to Plant Sorrel in Umatilla County, OR

Umatilla County, Oregon Zone 7a May

May to-do list for Umatilla County, Oregon

Here's what deserves your attention in Umatilla County, Oregon this month. Everything below is tailored to Zone 7a and timed around your local frost dates.

Avg. last frost April 23
Avg. first frost October 20
Soil temp (4") 60°F
Watering Critical
Pest pressure Low
Daylight 14.7 hrs
  1. Time to start sorrel inside

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

  2. Basket week: sorrel

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

Looking ahead to 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.

Umatilla County, Oregon is in USDA Zone 7a. The average last spring frost is April 23 and the first fall frost is October 20, giving you a growing season of approximately 180 days.

At an elevation of 2,195 feet, Umatilla County receives approximately 14.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Sorrel during the growing season. With low rainfall, drip irrigation is essential for growing Sorrel successfully. Mulch heavily to conserve soil moisture.

Umatilla County, OR (Zone 7a) Moderate season
180 days
Last Spring Frost April 23
180 growing days
First Fall Frost October 20
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Umatilla County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (86 days to spare)
Start indoors: Mar 4 Transplant: Apr 1 🍅 Harvest: May 13 – Jul 15
Recommended (50%) ✓ Fits season (82 days to spare)
Start indoors: Mar 19 Transplant: Apr 16 🍅 Harvest: May 28 – Jul 30
Safe Start (90%) ✓ Fits season (81 days to spare)
Start indoors: Apr 8 Transplant: May 6 🍅 Harvest: Jun 17 – Aug 19

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 Umatilla County

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

Soil pH

Your soil pH (5.2–6.8) overlaps with Sorrel's range (5.5–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.1%) — 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

5
successive plantings in your 180-day season

Sow every 4.6 weeks. Last sowing by Aug 21 to harvest before frost.

For a dedicated fall crop, sow by Aug 11.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.3″/week
You supply
0.7″/week
Watering frequency 1-2 times/week
Season total 1,056 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 1.8" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 1.3" 0" ❄️ Dormant
Apr 4.3" 1.1" 3.2" 🚿 Regular watering
May 4.3" 0.9" 3.4" 🚿 Regular watering
Jun 4.3" 0.6" 3.7" 🚿 Regular watering
Jul 4.3" 0.3" 4" 🚿 Regular watering
Aug 4.3" 0.3" 4" 🚿 Regular watering
Sep 4.3" 0.6" 3.7" 🚿 Regular watering
Oct 4.3" 1.4" 2.9" 🚿 Regular watering
Nov 2.4" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Umatilla 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 ~725 GDD — county provides 2,610 GDD Excellent fit

Sorrel Planting Timeline — Umatilla County, OR

Sorrel Planting Calendar

Activity When Date Range
Start Indoors March 19 Mar 19 – Apr 2
Transplant Outdoors April 16 Apr 16 – Apr 30
Direct Sow April 9 Apr 9 – Apr 30
Harvest May 28 May 28 – Jul 30
Fall Sowing August 11 Aug 11 – Aug 25

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

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 5.5–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

180 days in Umatilla County

Growing Tips for Sorrel in Umatilla County

Direct sow Sorrel outdoors after April 23 in Umatilla County when soil has warmed and frost danger has passed.

Your generous 180.0-day season in Umatilla County allows multiple plantings of Sorrel. Sow every 20.0 days for continuous harvest.

Umatilla County receives only 15" of rain annually. Sorrel needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Umatilla County, OR?

Umatilla County is in Zone 7a with an average last frost of April 23. Plan your Sorrel planting based on this frost date — see the calendar above for exact timing.

What planting zone is Umatilla County, OR?

Umatilla County, Oregon is in USDA Hardiness Zone 7a. The average last spring frost is April 23 and first fall frost is October 20.

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Your Umatilla County Garden Planner — Free

A 24-page printable planner built for Umatilla County (Zone 7a). 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 Umatilla 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.