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When to Plant Spinach in Wheeler County, OR

Spinach is a nutrient-packed cool-season green that grows quickly in spring and fall. It is rich in iron, vitamins, and antioxidants and excellent raw or cooked.

Wheeler County, Oregon is in USDA Zone 5b. The average last spring frost is May 23 and the first fall frost is September 23, giving you a growing season of approximately 123 days.

At an elevation of 2,175 feet, Wheeler County receives approximately 22.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Spinach to ensure they mature before fall.

Wheeler County, OR (Zone 5b) Short season
123 days
Last Spring Frost May 23
123 growing days
First Fall Frost September 23

Wheeler County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (19 days to spare)
Start indoors: Apr 11 Transplant: May 16 🍅 Harvest: Jun 20 – Aug 22
Recommended (50%) ✓ Fits season (25 days to spare)
Start indoors: Apr 18 Transplant: May 23 🍅 Harvest: Jun 27 – Aug 29
Safe Start (90%) ✓ Fits season (27 days to spare)
Start indoors: May 15 Transplant: Jun 19 🍅 Harvest: Jul 24 – Sep 25

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 Wheeler County

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

Soil pH

Your soil pH (5.2โ€“6.3) is more acidic than Spinach prefers (6.5โ€“7.5). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Wheeler County is excellent for Spinach โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.7%) โ€” Spinach will thrive.

How to Plant Spinach

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

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

Succession Planting Spinach

4
successive plantings in your 123-day season

Sow every 4 weeks. Last sowing by Aug 04 to harvest before frost.

For a dedicated fall crop, sow by Jul 15.

Plant Water Budget

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

Monthly Watering Guide for Spinach

Spinach needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Spinach Needs Rainfall You Supplement Action
Jan โ€” 3" 0" โ„๏ธ Dormant
Feb โ€” 2.3" 0" โ„๏ธ Dormant
Mar โ€” 2.6" 0" โ„๏ธ Dormant
Apr โ€” 1.6" 0" โ„๏ธ Dormant
May 3" 1.5" 1.5" ๐Ÿšฟ Regular watering
Jun 3" 1" 2" ๐Ÿšฟ Regular watering
Jul 3" 0.4" 2.6" ๐Ÿšฟ Regular watering
Aug 3" 0.4" 2.6" ๐Ÿšฟ Regular watering
Sep 3" 0.8" 2.2" ๐Ÿšฟ Regular watering
Oct โ€” 2.1" 0" โ„๏ธ Dormant
Nov โ€” 3.3" 0" โ„๏ธ Dormant
Dec โ€” 3.8" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in Wheeler County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Spinach 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" โ€” every day above 50ยฐF 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.

Spinach needs ~521 GDD — county provides 1,506 GDD Excellent fit

Spinach Planting Timeline โ€” Wheeler County, OR

Spinach Planting Calendar

Activity When Date Range
Start Indoors April 18 Apr 18 โ€“ May 2
Transplant Outdoors May 23 May 23 โ€“ Jun 6
Direct Sow May 9 May 9 โ€“ May 30
Harvest June 27 Jun 27 โ€“ Aug 29
Fall Sowing July 15 Jul 15 โ€“ Jul 29

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Partial Shade (3-6 hours)

๐Ÿ’ง Water

0.7"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

35โ€“50 days

๐Ÿงช Soil pH

Needs 6.5โ€“7.5 ยท Your soil: too_acidic

๐Ÿ—บ๏ธ USDA Zone

Zone 5b

๐Ÿ“† Growing Season

123 days in Wheeler County

Growing Tips for Spinach in Wheeler County

Direct sow Spinach outdoors after May 23 in Wheeler County when soil has warmed and frost danger has passed.

General growing tips

Direct sow as soon as soil can be worked in spring. Plant in partial shade for summer crops to delay bolting. Succession plant every 2 weeks for continuous harvest.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

๐ŸŒพ Save Your Own Spinach Seeds
Life Cycle Annual
Pollination Wind Pollinated
How to Collect Let plants bolt. Harvest seed stalks when seeds turn tan.
Storage Store airtight; viable 5 years at 35ยฐF, under 45% humidity.

Wind pollinated โ€” isolate 1/2 mile for purity. Easy to let bolt in heat.

Frequently Asked Questions

When should I plant Spinach in Wheeler County, OR?

Wheeler County is in Zone 5b with an average last frost of May 23. Plan your Spinach planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Wheeler County, OR?

Wheeler County, Oregon is in USDA Hardiness Zone 5b. The average last spring frost is May 23 and first fall frost is September 23.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Wheeler County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Wheeler County, OR. Local conditions may vary. Last updated: April 2026.