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When to Plant Zucchini in Coconino County, AZ

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.

Coconino County, Arizona is in USDA Zone 5b. The average last spring frost is May 28 and the first fall frost is September 27, giving you a growing season of approximately 122 days.

At an elevation of 7,869 feet, Coconino County receives approximately 13.9 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 96ยฐF, so Zucchini may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring โ€” great for early planting โ€” but Zucchini will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Zucchini successfully. Mulch heavily to conserve soil moisture.

Coconino County, AZ (Zone 5b) Short season
122 days
Last Spring Frost May 28
122 growing days
First Fall Frost September 27

Coconino County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.2-8.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (32 days to spare)
Start indoors: Mar 13 Transplant: May 1 🍅 Harvest: Jun 19 – Aug 14
Recommended (50%) ✓ Fits season (3 days to spare)
Start indoors: Apr 23 Transplant: Jun 11 🍅 Harvest: Jul 30 – Sep 24
Safe Start (90%) ✓ Fits season (15 days to spare)
Start indoors: May 20 Transplant: Jul 8 🍅 Harvest: Aug 26 – Oct 21

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 Coconino County

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

Soil pH

Your soil pH (7.2โ€“8.6) is more alkaline than Zucchini prefers (6.0โ€“7.5). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Coconino County warms quickly in spring but drains fast. Zucchini will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Zucchini.

Organic Matter

Organic matter is low (0.8%). Add 2-3 inches of compost before planting Zucchini.

How to Plant Zucchini

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

Succession Planting Zucchini

3
successive plantings in your 122-day season

Sow every 5.1 weeks. Last sowing by Jul 29 to harvest before frost.

Plant Water Budget

Plant needs
1.2″/week
Rainfall provides
0.5″/week
You supply
1.3″/week
Watering frequency 2-3 times/week
Season total 1,409 gal / 100 sq ft
Drought risk

Water stress score is 10/10 โ€” 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 โ€” 1" 0" โ„๏ธ Dormant
Feb โ€” 0.7" 0" โ„๏ธ Dormant
Mar โ€” 0.8" 0" โ„๏ธ Dormant
Apr โ€” 0.4" 0" โ„๏ธ Dormant
May 5.2" 0.3" 4.9" ๐Ÿšฟ Regular watering
Jun 5.2" 0.4" 4.8" ๐Ÿšฟ Regular watering
Jul 5.2" 2.6" 2.6" ๐Ÿšฟ Regular watering
Aug 5.2" 3" 2.2" ๐Ÿ’ง Light watering
Sep 5.2" 1.7" 3.5" ๐Ÿšฟ Regular watering
Oct โ€” 1.3" 0" โ„๏ธ Dormant
Nov โ€” 0.8" 0" โ„๏ธ Dormant
Dec โ€” 0.9" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in Coconino County). Supplement amounts are based on average rainfall โ€” 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" 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.

Zucchini needs ~1,155 GDD — county provides 2,684 GDD Excellent fit

Zucchini Planting Timeline โ€” Coconino County, AZ

Zucchini Planting Calendar

Activity When Date Range
Start Indoors April 23 Apr 23 โ€“ May 7
Transplant Outdoors June 11 Jun 11 โ€“ Jun 25
Direct Sow June 4 Jun 4 โ€“ Jun 25
Harvest July 30 Jul 30 โ€“ Sep 24

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Start Indoors
May Start Indoors
June Transplant Outdoors Direct Sow
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

1.2"/week ยท 2-3 times/week

๐Ÿ“… Days to Maturity

45โ€“60 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 5b

๐Ÿ“† Growing Season

122 days in Coconino County

Growing Tips for Zucchini in Coconino County

Direct sow Zucchini outdoors after May 28 in Coconino County when soil has warmed and frost danger has passed.

Sandy soil in Coconino County dries quickly โ€” mulch Zucchini with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 96ยฐF in Coconino County, provide afternoon shade for Zucchini and water deeply in the morning.

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.

Coconino County receives only 14" of rain annually. Zucchini needs consistent moisture โ€” 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 Coconino County

Quick-producing varieties for shorter seasons

Black Beauty (50d) Raven (48d) Eight Ball (40d)

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Zucchini in Coconino County, AZ?

Coconino County is in Zone 5b with an average last frost of May 28. Plan your Zucchini planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Coconino County, AZ?

Coconino County, Arizona is in USDA Hardiness Zone 5b. The average last spring frost is May 28 and first fall frost is September 27.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Coconino County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Coconino County, AZ. Local conditions may vary. Last updated: April 2026.