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When to Plant Spinach in Osborne County, KS

Osborne County, Kansas Zone 6a May

May in Osborne County, Kansas — your action list

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Osborne County, Kansas.

Avg. last frost April 23
Avg. first frost October 14
Soil temp (4") 58°F
Watering Low
Pest pressure Low
Daylight 14.2 hrs
  1. Indoor seed-starting week for spinach

    You're about 23 weeks out from your last frost — the perfect window to get these germinating indoors.

  2. Harvest spinach as they ripen

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

Coming up in June — start thinking about
  • 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.

Osborne County, Kansas is in USDA Zone 6a. The average last spring frost is April 23 and the first fall frost is October 14, giving you a growing season of approximately 174 days.

At an elevation of 608 feet, Osborne County receives approximately 31.8 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Spinach during the growing season.

Osborne County, KS (Zone 6a) Moderate season
174 days
Last Spring Frost April 23
174 growing days
First Fall Frost October 14
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Osborne County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (76 days to spare)
Start indoors: Mar 13 Transplant: Apr 17 🍅 Harvest: May 22 – Jul 24
Recommended (50%) ✓ Fits season (76 days to spare)
Start indoors: Mar 19 Transplant: Apr 23 🍅 Harvest: May 28 – Jul 30
Safe Start (90%) ✓ Fits season (74 days to spare)
Start indoors: Apr 2 Transplant: May 7 🍅 Harvest: Jun 11 – Aug 13

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 Osborne County

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

Soil pH

Your soil pH (6.8–7.5) is within Spinach's preferred range (6.5–7.5).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.1%) — 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 174-day season

Sow every 4 weeks. Last sowing by Aug 25 to harvest before frost.

For a dedicated fall crop, sow by Aug 05.

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
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 0.9" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 3" 3.8" 0" ✅ Rainfall sufficient
May 3" 4.3" 0" ✅ Rainfall sufficient
Jun 3" 4.5" 0" ✅ Rainfall sufficient
Jul 3" 3.9" 0" ✅ Rainfall sufficient
Aug 3" 4.2" 0" ✅ Rainfall sufficient
Sep 3" 3" 0" ✅ Rainfall sufficient
Oct 3" 2.1" 0.9" 💧 Light watering
Nov 1.1" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Osborne 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 ~648 GDD — county provides 2,653 GDD Excellent fit

Spinach Planting Timeline — Osborne County, KS

Spinach Planting Calendar

Activity When Date Range
Start Indoors March 19 Mar 19 – Apr 2
Transplant Outdoors April 23 Apr 23 – May 7
Direct Sow April 9 Apr 9 – Apr 30
Harvest May 28 May 28 – Jul 30
Fall Sowing August 5 Aug 5 – Aug 19

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors Transplant Outdoors Direct Sow
May Transplant Outdoors 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

0.7"/week · Natural rainfall sufficient

📅 Days to Maturity

35–50 days

🧪 Soil pH

Needs 6.5–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

174 days in Osborne County

Growing Tips for Spinach in Osborne County

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

Your generous 174.0-day season in Osborne 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.

Recommended Spinach Varieties for Osborne County

Slow-bolting spinach for warm springs — best as fall crop here

Bloomsdale Long Standing Tyee Space

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 Osborne County, KS?

Osborne County is in Zone 6a with an average last frost of April 23. Plan your Spinach planting based on this frost date — see the calendar above for exact timing.

What planting zone is Osborne County, KS?

Osborne County, Kansas is in USDA Hardiness Zone 6a. The average last spring frost is April 23 and first fall frost is October 14.

🌱

Your Osborne County Garden Planner — Free

A 24-page printable planner built for Osborne County (Zone 6a). 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 Osborne County, KS. 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.