When to plant Spinach in Iron County, MI
Plant Spinach in Iron County after May 26; the prime window is May 19–June 9. A second sowing from June 29 to July 13 extends the harvest into fall.
When to Plant Spinach in Iron County, MI
August in Iron County, Michigan — your action list
We've pulled the most time-sensitive tasks for Iron County, Michigan this August and put them front and centre. Tackle them in order.
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Bring in the spinach
Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.
Coming up in September — start thinking about
- First harvests: spinach
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.
Iron County, Michigan is in USDA Zone 4a. The average last spring frost is May 26 and the first fall frost is September 21, giving you a growing season of approximately 118 days.
At an elevation of 531 feet, Iron County receives approximately 42 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Spinach to ensure they mature before fall.
Iron County Soil Profile
Soil Type
Silt Loam
Soil pH
6.1-6.9
Drainage
Well Drained
Spinach Planting Risk Windows
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 Iron County
How your county's soil matches Spinach's growing requirements.
Soil pH
Your soil pH (6.1–6.9) overlaps with Spinach's range (6.5–7.5), though not a perfect match.
Soil Texture
The silt loam soil in Iron County is excellent for Spinach — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.5%) — Spinach will thrive.
How to Plant Spinach
Fall planting: Sow 12 weeks before your first frost date for a fall harvest.
Succession Planting Spinach
Sow every 4 weeks. Last sowing by Aug 02 to harvest before frost.
For a dedicated fall crop, sow by Jun 29.
Spinach Water Budget
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 | — | 1.9" | 0" | ❄️ Dormant |
| Feb | — | 2.1" | 0" | ❄️ Dormant |
| Mar | — | 3.2" | 0" | ❄️ Dormant |
| Apr | — | 3.9" | 0" | ❄️ Dormant |
| May | 3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Jun | 3" | 4.8" | 0" | ✅ Rainfall sufficient |
| Jul | 3" | 4.3" | 0" | ✅ Rainfall sufficient |
| Aug | 3" | 4.7" | 0" | ✅ Rainfall sufficient |
| Sep | 3" | 3.8" | 0" | ✅ Rainfall sufficient |
| Oct | — | 3" | 0" | ❄️ Dormant |
| Nov | — | 3.3" | 0" | ❄️ Dormant |
| Dec | — | 2.5" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Iron 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 Planting Timeline — Iron County, MI
Spinach Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 14 | Apr 14 – Apr 28 |
| Transplant Outdoors | May 26 | May 26 – Jun 9 |
| Direct Sow | May 19 | May 19 – Jun 9 |
| Harvest | June 30 | Jun 30 – Sep 1 |
| Fall Sowing | June 29 | Jun 29 – Jul 13 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | Transplant Outdoors Direct Sow Fall Sowing Harvest |
| July | Fall Sowing Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
0.7"/week · Natural rainfall sufficient
📅 Days to Maturity
35–50 days
🧪 Soil pH
Needs 6.5–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 4a
📆 Growing Season
118 days in Iron County
Growing Tips for Spinach in Iron County
Direct sow Spinach outdoors after May 26 in Iron 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 →
Wind pollinated — isolate 1/2 mile for purity. Easy to let bolt in heat.
Spinach in Other Locations
Frequently Asked Questions
When should I plant Spinach in Iron County, MI?
Iron County is in Zone 4a with an average last frost of May 26. Plan your Spinach planting based on this frost date — see the calendar above for exact timing.
What planting zone is Iron County, MI?
Iron County, Michigan is in USDA Hardiness Zone 4a. The average last spring frost is May 26 and first fall frost is September 21.
When should I plant Spinach in Iron County, MI?
In Iron County, MI, plant Spinach after the last frost (around May 26) and before the first frost (around September 21). Best results when soil holds above 50°F.
What growing zone is Iron County, MI for Spinach?
Iron County sits in USDA Zone 4a. Spinach grows reliably in zones 2a through 10b, so it's a good fit here.
Can Spinach grow in Iron County's climate?
Yes — Spinach grows well in Iron County's temperate climate. Iron County averages a 118-day frost-free season, with last frost around May 26 and first frost around September 21.
Your Iron County Garden Planner — Free
A 22-page printable planner built for Iron County (Zone 4a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.