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When to Plant Spinach in Bear Lake County, ID

Bear Lake County, Idaho Zone 5a May

May in Bear Lake County, Idaho — your action list

A quick May briefing for Bear Lake County, Idaho gardeners — what's urgent, what's next, and what can wait.

Avg. last frost May 24
Avg. first frost September 24
Soil temp (4") 42°F
Watering High
Pest pressure Low
Daylight 14.4 hrs
  1. Harden off and plant spinach

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

  2. Direct-sow spinach

    These tolerate cool soil, so you're not gambling by sowing now.

Coming up in June — start thinking about
  • Starting indoors: spinach
  • First harvests: spinach

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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.

Bear Lake County, Idaho is in USDA Zone 5a. The average last spring frost is May 24 and the first fall frost is September 24, giving you a growing season of approximately 123 days.

At an elevation of 5,220 feet, Bear Lake County receives approximately 18.6 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Spinach to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Spinach successfully. Mulch heavily to conserve soil moisture.

Bear Lake County, ID (Zone 5a) Short season
123 days
Last Spring Frost May 24
123 growing days
First Fall Frost September 24
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Bear Lake County Soil Profile

Soil Type

Loam

Soil pH

6.7-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (18 days to spare)
Start indoors: Apr 1 Transplant: May 6 🍅 Harvest: Jun 10 – Aug 12
Recommended (50%) ✓ Fits season (25 days to spare)
Start indoors: Apr 19 Transplant: May 24 🍅 Harvest: Jun 28 – Aug 30
Safe Start (90%) ✓ Fits season (22 days to spare)
Start indoors: May 18 Transplant: Jun 22 🍅 Harvest: Jul 27 – Sep 28

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 Bear Lake County

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

Soil pH

Your soil pH (6.7–8.2) overlaps with Spinach's range (6.5–7.5), though not a perfect match.

Soil Texture

The loam soil in Bear Lake County is excellent for Spinach — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Spinach.

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 05 to harvest before frost.

For a dedicated fall crop, sow by Jul 16.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.6″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 85 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.4" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 1.9" 0" ❄️ Dormant
May 3" 2.5" 0.5" 💧 Light watering
Jun 3" 1.1" 1.9" 🚿 Regular watering
Jul 3" 1.6" 1.4" 💧 Light watering
Aug 3" 2" 1" 💧 Light watering
Sep 3" 1.5" 1.5" 🚿 Regular watering
Oct 1.7" 0" ❄️ Dormant
Nov 1.4" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Bear Lake County). Supplement amounts are based on average rainfall — 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" — 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.

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

Spinach Planting Timeline — Bear Lake County, ID

Spinach Planting Calendar

Activity When Date Range
Start Indoors April 19 Apr 19 – May 3
Transplant Outdoors May 24 May 24 – Jun 7
Direct Sow May 10 May 10 – May 31
Harvest June 28 Jun 28 – Aug 30
Fall Sowing July 16 Jul 16 – Jul 30

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

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.7"/week · Only during dry spells

📅 Days to Maturity

35–50 days

🧪 Soil pH

Needs 6.5–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

123 days in Bear Lake County

Growing Tips for Spinach in Bear Lake County

Direct sow Spinach outdoors after May 24 in Bear Lake 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 →

🌾 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 35°F, under 45% humidity.

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

Frequently Asked Questions

When should I plant Spinach in Bear Lake County, ID?

Bear Lake County is in Zone 5a with an average last frost of May 24. Plan your Spinach planting based on this frost date — see the calendar above for exact timing.

What planting zone is Bear Lake County, ID?

Bear Lake County, Idaho is in USDA Hardiness Zone 5a. The average last spring frost is May 24 and first fall frost is September 24.

🌱

Your Bear Lake County Garden Planner — Free

A 24-page printable planner built for Bear Lake County (Zone 5a). 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 Bear Lake County, ID. 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.