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When to Plant Acorn Squash in Lake County, CO

Lake County, Colorado Zone 5a May

Your May planting checklist for Lake County, Colorado

Here's what deserves your attention in Lake County, Colorado this month. Everything below is tailored to Zone 5a and timed around your local frost dates.

Avg. last frost June 21
Avg. first frost August 30
Soil temp (4") 34°F
Watering High
Pest pressure Low
Daylight 14.1 hrs
Looking ahead to June
  • Direct-sowing: acorn squash

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Acorn squash is a small winter squash with dark green, ribbed skin and mildly sweet orange flesh. It is perfect for stuffing and roasting as individual servings.

Lake County, Colorado is in USDA Zone 5a. The average last spring frost is June 21 and the first fall frost is August 30, giving you a growing season of approximately 70 days.

At an elevation of 7,687 feet, Lake County receives approximately 21.2 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Acorn Squash to ensure they mature before fall.

Lake County, CO (Zone 5a) Very short season
70 days
Last Spring Frost June 21
70 growing days
First Fall Frost August 30

Lake County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: May 12 Transplant: Jun 30 🍅 Harvest: Sep 22 – Oct 27
Recommended (50%) ✗ May not fit
Start indoors: May 17 Transplant: Jul 5 🍅 Harvest: Sep 27 – Nov 1
Safe Start (90%) ✗ May not fit
Start indoors: May 23 Transplant: Jul 11 🍅 Harvest: Oct 3 – Nov 7

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 Lake County

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

Soil pH

Your soil pH (6.6–8.2) is more alkaline than Acorn Squash prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Lake County is excellent for Acorn Squash — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.9%). Annual compost additions will help Acorn Squash.

How to Plant Acorn Squash

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

Plant Water Budget

Plant needs
1.1″/week
Rainfall provides
1.3″/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 Acorn Squash

Acorn 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 Acorn Squash Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 1.8" 0" ❄️ Dormant
Apr 2.1" 0" ❄️ Dormant
May 2.7" 0" ❄️ Dormant
Jun 4.8" 1.4" 3.4" 🚿 Regular watering
Jul 4.8" 2.1" 2.7" 🚿 Regular watering
Aug 4.8" 2.2" 2.6" 🚿 Regular watering
Sep 1.6" 0" ❄️ Dormant
Oct 2.1" 0" ❄️ Dormant
Nov 1.6" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

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

Acorn 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" — 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.

Acorn Squash needs ~1,102 GDD — county provides 857 GDD May not mature

Acorn Squash Planting Timeline — Lake County, CO

Acorn Squash Planting Calendar

Activity When Date Range
Start Indoors May 17 May 17 – May 31
Transplant Outdoors July 5 Jul 5 – Jul 19
Direct Sow June 28 Jun 28 – Jul 19
Harvest September 27 Sep 27 – Nov 1

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.1"/week · Natural rainfall sufficient

📅 Days to Maturity

80–100 days

🧪 Soil pH

Needs 5.5–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5a

📆 Growing Season

70 days in Lake County

Growing Tips for Acorn Squash in Lake County

Direct sow Acorn Squash outdoors after June 21 in Lake County when soil has warmed and frost danger has passed.

Your 70.0-day growing season in Lake County is tight for Acorn Squash (80.0-100.0 days to maturity). Start indoors and choose early-maturing varieties.

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

Lake County receives only 21" of rain annually. Acorn Squash needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow after last frost. Harvest when the ground spot turns orange and the skin is hard. Acorn squash has a shorter storage life than butternut, lasting about 2 months.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Acorn Squash in Lake County, CO?

Lake County is in Zone 5a with an average last frost of June 21. Plan your Acorn Squash planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lake County, CO?

Lake County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is June 21 and first fall frost is August 30.

🌱

Your Lake County Garden Planner — Free

A 24-page printable planner built for Lake County (Zone 5a). 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 Lake County, CO. 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.