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When to Plant Spinach in Philadelphia County, PA

Philadelphia County, Pennsylvania Zone 7b May

May to-do list for Philadelphia County, Pennsylvania

Each item below is timed to Philadelphia County, Pennsylvania's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 16
Avg. first frost October 24
Soil temp (4") 68°F
Watering Low
Pest pressure Moderate
Daylight 14.2 hrs
  1. Start spinach under lights

    You're about 24 weeks out from your last frost — the perfect window to get these germinating indoors.

  2. It's harvest week for spinach

    If you can't use it all right away, check the food-preservation section of your planner.

A few tasks this May that'll pay off in June
  • 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.

Philadelphia County, Pennsylvania is in USDA Zone 7b. The average last spring frost is April 16 and the first fall frost is October 24, giving you a growing season of approximately 191 days.

At an elevation of 996 feet, Philadelphia County receives approximately 48.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 93°F, providing good warmth for Spinach during the growing season.

Philadelphia County, PA (Zone 7b) Moderate season
191 days
Last Spring Frost April 16
191 growing days
First Fall Frost October 24
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Philadelphia County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (90 days to spare)
Start indoors: Mar 9 Transplant: Apr 13 🍅 Harvest: May 18 – Jul 20
Recommended (50%) ✓ Fits season (93 days to spare)
Start indoors: Mar 12 Transplant: Apr 16 🍅 Harvest: May 21 – Jul 23
Safe Start (90%) ✓ Fits season (79 days to spare)
Start indoors: Apr 6 Transplant: May 11 🍅 Harvest: Jun 15 – Aug 17

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 Philadelphia County

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

Soil pH

Your soil pH (5.2–6.7) is more acidic than Spinach prefers (6.5–7.5). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (4.0%). 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

6
successive plantings in your 191-day season

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

For a dedicated fall crop, sow by Aug 15.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
1.1″/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 3.9" 0" ❄️ Dormant
Feb 3.7" 0" ❄️ Dormant
Mar 3.8" 0" ❄️ Dormant
Apr 3" 4.5" 0" ✅ Rainfall sufficient
May 3" 4.5" 0" ✅ Rainfall sufficient
Jun 3" 3.9" 0" ✅ Rainfall sufficient
Jul 3" 4.5" 0" ✅ Rainfall sufficient
Aug 3" 4.5" 0" ✅ Rainfall sufficient
Sep 3" 3.6" 0" ✅ Rainfall sufficient
Oct 3" 4.3" 0" ✅ Rainfall sufficient
Nov 3.3" 0" ❄️ Dormant
Dec 3.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Philadelphia 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 ~839 GDD — county provides 3,772 GDD Excellent fit

Spinach Planting Timeline — Philadelphia County, PA

Spinach Planting Calendar

Activity When Date Range
Start Indoors March 12 Mar 12 – Mar 26
Transplant Outdoors April 16 Apr 16 – Apr 30
Direct Sow April 2 Apr 2 – Apr 23
Harvest May 21 May 21 – Jul 23
Fall Sowing August 15 Aug 15 – Aug 29

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 7b

📆 Growing Season

191 days in Philadelphia County

Growing Tips for Spinach in Philadelphia County

Direct sow Spinach outdoors after April 16 in Philadelphia County when soil has warmed and frost danger has passed.

Summer highs in Philadelphia County reach 93°F — grow Spinach as a spring or fall crop. Use shade cloth if planting in summer.

Your generous 191.0-day season in Philadelphia 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 Philadelphia 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 Philadelphia County, PA?

Philadelphia County is in Zone 7b with an average last frost of April 16. Plan your Spinach planting based on this frost date — see the calendar above for exact timing.

What planting zone is Philadelphia County, PA?

Philadelphia County, Pennsylvania is in USDA Hardiness Zone 7b. The average last spring frost is April 16 and first fall frost is October 24.

🌱

Your Philadelphia County Garden Planner — Free

A 24-page printable planner built for Philadelphia County (Zone 7b). 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 Philadelphia County, PA. 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.