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When to Plant Butternut Squash in Riley County, KS

Butternut squash is a popular winter squash with a long neck, small seed cavity, and sweet, nutty orange flesh. It stores exceptionally well for months.

Riley County, Kansas is in USDA Zone 6a. The average last spring frost is April 17 and the first fall frost is October 18, giving you a growing season of approximately 184 days.

At an elevation of 551 feet, Riley County receives approximately 32.9 inches of rainfall annually with predominantly loam soil. Summer highs average 85ยฐF, providing good warmth for Butternut Squash during the growing season.

Riley County, KS (Zone 6a) Moderate season
184 days
Last Spring Frost April 17
184 growing days
First Fall Frost October 18

Riley County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (42 days to spare)
Start indoors: Mar 9 Transplant: Apr 27 🍅 Harvest: Jul 27 – Aug 31
Recommended (50%) ✓ Fits season (44 days to spare)
Start indoors: Mar 13 Transplant: May 1 🍅 Harvest: Jul 31 – Sep 4
Safe Start (90%) ✓ Fits season (43 days to spare)
Start indoors: Mar 28 Transplant: May 16 🍅 Harvest: Aug 15 – Sep 19

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 Riley County

How your county's soil matches Butternut Squash's growing requirements.

Soil pH

Your soil pH (6.8โ€“7.7) is more alkaline than Butternut Squash prefers (6.0โ€“7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Riley County is excellent for Butternut Squash โ€” good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Butternut Squash.

Organic Matter

Organic matter is moderate (3.4%). Annual compost additions will help Butternut Squash.

How to Plant Butternut Squash

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

Plant Water Budget

Plant needs
1.1″/week
Rainfall provides
0.8″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 1,334 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Monthly Watering Guide for Butternut Squash

Butternut Squash needs approximately 1.1 inches of water per week (4.8" per month). Here's how your county's rainfall compares month by month.

Month Butternut Squash Needs Rainfall You Supplement Action
Jan โ€” 1" 0" โ„๏ธ Dormant
Feb โ€” 1.2" 0" โ„๏ธ Dormant
Mar โ€” 2.3" 0" โ„๏ธ Dormant
Apr 4.8" 3.1" 1.7" ๐Ÿ’ง Light watering
May 4.8" 4.3" 0.5" ๐Ÿ’ง Light watering
Jun 4.8" 5.5" 0" โœ… Rainfall sufficient
Jul 4.8" 4" 0.8" ๐Ÿ’ง Light watering
Aug 4.8" 4" 0.8" ๐Ÿ’ง Light watering
Sep 4.8" 3.1" 1.7" ๐Ÿ’ง Light watering
Oct 4.8" 2.3" 2.5" ๐Ÿšฟ Regular watering
Nov โ€” 1.2" 0" โ„๏ธ Dormant
Dec โ€” 0.9" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Riley County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Butternut Squash 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.

Butternut Squash needs ~1,341 GDD — county provides 2,530 GDD Excellent fit

Butternut Squash Planting Timeline โ€” Riley County, KS

Butternut Squash Planting Calendar

Activity When Date Range
Start Indoors March 13 Mar 13 โ€“ Mar 27
Transplant Outdoors May 1 May 1 โ€“ May 15
Direct Sow April 24 Apr 24 โ€“ May 15
Harvest July 31 Jul 31 โ€“ Sep 4

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1.1"/week ยท 2-3 times/week

๐Ÿ“… Days to Maturity

85โ€“110 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 6a

๐Ÿ“† Growing Season

184 days in Riley County

Growing Tips for Butternut Squash in Riley County

Direct sow Butternut Squash outdoors after April 17 in Riley County when soil has warmed and frost danger has passed.

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

General growing tips

Start seeds indoors 3 weeks early or direct sow after frost. Allow 6-8 feet for sprawling vines. Harvest when the skin is hard and uniformly tan. Cure in the sun for 10 days.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Butternut Squash in Riley County, KS?

Riley County is in Zone 6a with an average last frost of April 17. Plan your Butternut Squash planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Riley County, KS?

Riley County, Kansas is in USDA Hardiness Zone 6a. The average last spring frost is April 17 and first fall frost is October 18.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Riley County gardeners in Zone 6a organize planting dates, track what's growing, and never miss a planting window.

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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 Riley County, KS. Local conditions may vary. Last updated: April 2026.