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When to Plant Squash (Summer) in Knox County, IN

Knox County, Indiana Zone 6b May

May in Knox County, Indiana — your action list

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

Avg. last frost April 10
Avg. first frost October 23
Soil temp (4") 62°F
Watering Low
Pest pressure Low
Daylight 14.1 hrs
  1. Start squash (summer) indoors

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

Get ahead of June
  • First harvests: squash (summer)

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Summer squash includes zucchini, yellow crookneck, and pattypan varieties that are harvested young and tender. They are prolific producers in warm weather.

Knox County, Indiana is in USDA Zone 6b. The average last spring frost is April 10 and the first fall frost is October 23, giving you a growing season of approximately 196 days.

At an elevation of 735 feet, Knox County receives approximately 38.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Squash (Summer) during the growing season.

Knox County, IN (Zone 6b) Moderate season
196 days
Last Spring Frost April 10
196 growing days
First Fall Frost October 23

Knox County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (71 days to spare)
Start indoors: Mar 1 Transplant: Apr 19 🍅 Harvest: Jun 7 – Aug 9
Recommended (50%) ✓ Fits season (70 days to spare)
Start indoors: Mar 6 Transplant: Apr 24 🍅 Harvest: Jun 12 – Aug 14
Safe Start (90%) ✓ Fits season (70 days to spare)
Start indoors: Mar 20 Transplant: May 8 🍅 Harvest: Jun 26 – Aug 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 Knox County

How your county's soil matches Squash (Summer)'s growing requirements.

Soil pH

Your soil pH (6.0–7.2) is within Squash (Summer)'s preferred range (6.0–7.5).

Soil Texture

The silt loam soil in Knox County is excellent for Squash (Summer) — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.9%). Annual compost additions will help Squash (Summer).

How to Plant Squash (Summer)

1"
Planting Depth
30"
Between Plants
42"
Between Rows

Succession Planting Squash (Summer)

5
successive plantings in your 196-day season

Sow every 5.1 weeks. Last sowing by Aug 19 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 290 gal / 100 sq ft

Monthly Watering Guide for Squash (Summer)

Squash (Summer) needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Squash (Summer) Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 4.3" 3.8" 0.5" 💧 Light watering
May 4.3" 4.4" 0" ✅ Rainfall sufficient
Jun 4.3" 4.8" 0" ✅ Rainfall sufficient
Jul 4.3" 4" 0.3" 💧 Light watering
Aug 4.3" 4.2" 0.1" 💧 Light watering
Sep 4.3" 3.5" 0.8" 💧 Light watering
Oct 4.3" 2.7" 1.6" 💧 Light watering
Nov 3.1" 0" ❄️ Dormant
Dec 2.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Knox County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Squash (Summer) 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.

Squash (Summer) needs ~1,004 GDD — county provides 3,577 GDD Excellent fit

Squash (Summer) Planting Timeline — Knox County, IN

Squash (Summer) Planting Calendar

Activity When Date Range
Start Indoors March 6 Mar 6 – Mar 20
Transplant Outdoors April 24 Apr 24 – May 8
Direct Sow April 17 Apr 17 – May 8
Harvest June 12 Jun 12 – Aug 14

Plant 1" deep · 30" apart · Rows 42" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

45–65 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 6b

📆 Growing Season

196 days in Knox County

Growing Tips for Squash (Summer) in Knox County

Direct sow Squash (Summer) outdoors after April 10 in Knox County when soil has warmed and frost danger has passed.

Your generous 196.0-day season in Knox County allows multiple plantings of Squash (Summer). Sow every 22.0 days for continuous harvest.

Common pests for Squash (Summer) in this region include squash vine borer and cucumber beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow after last frost on mounds. Harvest frequently when fruits are 6-8 inches for best texture. Check plants daily as they grow rapidly in summer heat.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Squash (Summer) in Knox County, IN?

Knox County is in Zone 6b with an average last frost of April 10. Plan your Squash (Summer) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Knox County, IN?

Knox County, Indiana is in USDA Hardiness Zone 6b. The average last spring frost is April 10 and first fall frost is October 23.

🌱

Your Knox County Garden Planner — Free

A 24-page printable planner built for Knox County (Zone 6b). 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 Knox County, IN. 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.