When to Plant Zucchini in Boulder, UT
Your July gardening checklist
July is a pivotal month for Garfield County, Utah gardens. Focus on these tasks first and you'll set up the rest of the season for success.
-
Begin indoor sowing: zucchini
Your window is short. These crops want several weeks of indoor growth before they go outside.
-
Basket week: zucchini
Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.
Looking ahead to August
- First harvests: zucchini
Zucchini is an incredibly prolific summer squash that can produce an abundance of fruit from just a few plants. It is versatile in the kitchen from grilling to baking.
Boulder, Utah is in USDA Zone 6a. The average last spring frost is May 27 and the first fall frost is September 21, giving you a growing season of approximately 117 days.
At an elevation of 5,058 feet, Garfield County receives approximately 20.3 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Zucchini to ensure they mature before fall.
Boulder Soil Profile
Soil Type
Loam
Soil pH
6.5-7.7
Drainage
Well Drained
Zucchini Planting Risk Windows
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 Boulder
How your county's soil matches Zucchini's growing requirements.
Soil pH
Your soil pH (6.5–7.7) overlaps with Zucchini's range (6.0–7.5), though not a perfect match.
Soil Texture
The loam soil in Garfield County is excellent for Zucchini — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.2%). Annual compost additions will help Zucchini.
How to Plant Zucchini
Succession Planting Zucchini
Sow every 5.1 weeks. Last sowing by Jul 23 to harvest before frost.
Zucchini Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Zucchini
Zucchini needs approximately 1.2 inches of water per week (5.2" per month). Here's how your county's rainfall compares month by month.
| Month | Zucchini Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.4" | 0" | ❄️ Dormant |
| Feb | — | 1.3" | 0" | ❄️ Dormant |
| Mar | — | 1.9" | 0" | ❄️ Dormant |
| Apr | — | 2.1" | 0" | ❄️ Dormant |
| May | 5.2" | 2.3" | 2.9" | 🚿 Regular watering |
| Jun | 5.2" | 1.4" | 3.8" | 🚿 Regular watering |
| Jul | 5.2" | 1.6" | 3.6" | 🚿 Regular watering |
| Aug | 5.2" | 2" | 3.2" | 🚿 Regular watering |
| Sep | 5.2" | 1.8" | 3.4" | 🚿 Regular watering |
| Oct | — | 2" | 0" | ❄️ Dormant |
| Nov | — | 1.5" | 0" | ❄️ Dormant |
| Dec | — | 1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Garfield County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Zucchini 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.
Zucchini Planting Timeline — Boulder, UT
Zucchini Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 22 | Apr 22 – May 6 |
| Transplant Outdoors | June 10 | Jun 10 – Jun 24 |
| Direct Sow | June 3 | Jun 3 – Jun 24 |
| Harvest | July 29 | Jul 29 – Sep 23 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Start Indoors |
| June | Transplant Outdoors Direct Sow |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.2"/week · 1-2 times/week
📅 Days to Maturity
45–60 days
🧪 Soil pH
Needs 6–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 6a
📆 Growing Season
117 days in Garfield County
Growing Tips for Zucchini in Boulder
Direct sow Zucchini outdoors after May 27 in Garfield County when soil has warmed and frost danger has passed.
Common pests for Zucchini in this region include squash vine borer and cucumber beetles. Use row covers early in the season and inspect plants weekly.
Garfield County receives only 20" of rain annually. Zucchini needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
Direct sow after last frost. Harvest when fruits are 6-8 inches long for best flavor and texture. Check plants daily in summer as fruits can double in size overnight.
Recommended Zucchini Varieties for Boulder
Quick-producing varieties for shorter seasons
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Zucchini in Other Locations
Your Garfield County Garden Planner — Free
A 22-page printable planner built for Garfield 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.