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When to Plant Spinach in Kent County, MI

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.

Kent County, Michigan is in USDA Zone 5b. The average last spring frost is May 7 and the first fall frost is October 9, giving you a growing season of approximately 155 days.

At an elevation of 617 feet, Kent County receives approximately 32.8 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.

Kent County, MI (Zone 5b) Moderate season
155 days
Last Spring Frost May 7
155 growing days
First Fall Frost October 9

Kent County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (59 days to spare)
Start indoors: Mar 24 Transplant: Apr 28 🍅 Harvest: Jun 2 – Aug 4
Recommended (50%) ✓ Fits season (57 days to spare)
Start indoors: Apr 2 Transplant: May 7 🍅 Harvest: Jun 11 – Aug 13
Safe Start (90%) ✓ Fits season (54 days to spare)
Start indoors: Apr 21 Transplant: May 26 🍅 Harvest: Jun 30 – Sep 1

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 Kent County

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

Soil pH

Your soil pH (6.0โ€“7.0) overlaps with Spinach's range (6.5โ€“7.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Spinach.

Organic Matter

Organic matter is excellent (4.9%) 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

5
successive plantings in your 155-day season

Sow every 4 weeks. Last sowing by Aug 20 to harvest before frost.

For a dedicated fall crop, sow by Jul 31.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.9″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 29 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€” 1.4" 0" โ„๏ธ Dormant
Feb โ€” 1.4" 0" โ„๏ธ Dormant
Mar โ€” 2.2" 0" โ„๏ธ Dormant
Apr โ€” 3" 0" โ„๏ธ Dormant
May 3" 4.2" 0" โœ… Rainfall sufficient
Jun 3" 4.1" 0" โœ… Rainfall sufficient
Jul 3" 3.3" 0" โœ… Rainfall sufficient
Aug 3" 3.2" 0" โœ… Rainfall sufficient
Sep 3" 3" 0" โœ… Rainfall sufficient
Oct 3" 2.8" 0.2" ๐Ÿ’ง Light watering
Nov โ€” 2.5" 0" โ„๏ธ Dormant
Dec โ€” 1.7" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Oct in Kent 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 1,898 GDD Excellent fit

Spinach Planting Timeline โ€” Kent County, MI

Spinach Planting Calendar

Activity When Date Range
Start Indoors April 2 Apr 2 โ€“ Apr 16
Transplant Outdoors May 7 May 7 โ€“ May 21
Direct Sow April 23 Apr 23 โ€“ May 14
Harvest June 11 Jun 11 โ€“ Aug 13
Fall Sowing July 31 Jul 31 โ€“ Aug 14

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 Direct Sow
May Transplant Outdoors Direct Sow
June Harvest
July Fall Sowing Harvest
August Fall Sowing 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 Only during dry spells

๐Ÿ“… Days to Maturity

35โ€“50 days

๐Ÿงช Soil pH

Needs 6.5โ€“7.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 5b

๐Ÿ“† Growing Season

155 days in Kent County

Growing Tips for Spinach in Kent County

Direct sow Spinach outdoors after May 07 in Kent County when soil has warmed and frost danger has passed.

Your generous 155.0-day season in Kent County allows multiple plantings of Spinach. Sow every 17.0 days for continuous harvest.

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 Kent County, MI?

Kent County is in Zone 5b with an average last frost of May 7. Plan your Spinach planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Kent County, MI?

Kent County, Michigan is in USDA Hardiness Zone 5b. The average last spring frost is May 7 and first fall frost is October 9.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Kent 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 Kent County, MI. Local conditions may vary. Last updated: April 2026.