When to plant Zucchini in Cass County, IA
For Zucchini in Cass County, the safe spring window opens around May 2 and closes around May 23. Last expected frost is April 25, first fall frost October 9, giving a 167-day growing season.
When to Plant Zucchini in Cass County, IA
July to-do list for Cass County, Iowa
Welcome to July in Zone 5b. These are the moves that will have the biggest impact on your growing season.
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Bring in the zucchini
Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.
August prep starts now
- 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.
Cass County, Iowa is in USDA Zone 5b. The average last spring frost is April 25 and the first fall frost is October 9, giving you a growing season of approximately 167 days.
At an elevation of 1,043 feet, Cass County receives approximately 31.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Zucchini during the growing season.
Cass County Soil Profile
Soil Type
Silt Loam
Soil pH
6.2-6.7
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 Cass County
How your county's soil matches Zucchini's growing requirements.
Soil pH
Your soil pH (6.2–6.7) is within Zucchini's preferred range (6.0–7.5).
Soil Texture
The silt loam soil in Cass County is excellent for Zucchini — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.4%) — Zucchini will thrive.
How to Plant Zucchini
Succession Planting Zucchini
Sow every 5.1 weeks. Last sowing by Aug 10 to harvest before frost.
Zucchini Water Budget
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 | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.6" | 0" | ❄️ Dormant |
| Mar | — | 1.9" | 0" | ❄️ Dormant |
| Apr | 5.2" | 2.9" | 2.3" | 💧 Light watering |
| May | 5.2" | 3.4" | 1.8" | 💧 Light watering |
| Jun | 5.2" | 3.7" | 1.5" | 💧 Light watering |
| Jul | 5.2" | 3.4" | 1.8" | 💧 Light watering |
| Aug | 5.2" | 3.4" | 1.8" | 💧 Light watering |
| Sep | 5.2" | 2.9" | 2.3" | 💧 Light watering |
| Oct | 5.2" | 2.4" | 2.8" | 🚿 Regular watering |
| Nov | — | 2.1" | 0" | ❄️ Dormant |
| Dec | — | 1.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Cass 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 — Cass County, IA
Zucchini Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 21 | Mar 21 – Apr 4 |
| Transplant Outdoors | May 9 | May 9 – May 23 |
| Direct Sow | May 2 | May 2 – May 23 |
| Harvest | June 27 | Jun 27 – Aug 22 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | Harvest |
| July | Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.2"/week · 1-2 times/week
📅 Days to Maturity
45–60 days
🧪 Soil pH
Needs 6–7.5 · Your soil: ideal
🗺️ USDA Zone
Zone 5b
📆 Growing Season
167 days in Cass County
Growing Tips for Zucchini in Cass County
Direct sow Zucchini outdoors after April 25 in Cass County when soil has warmed and frost danger has passed.
Your generous 167.0-day season in Cass County allows multiple plantings of Zucchini. Sow every 22.0 days for continuous harvest.
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.
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.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Zucchini in Other Locations
Frequently Asked Questions
When should I plant Zucchini in Cass County, IA?
Cass County is in Zone 5b with an average last frost of April 25. Plan your Zucchini planting based on this frost date — see the calendar above for exact timing.
What planting zone is Cass County, IA?
Cass County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 25 and first fall frost is October 9.
When should I plant Zucchini in Cass County, IA?
In Cass County, IA, plant Zucchini after the last frost (around April 25) and before the first frost (around October 9). Best results when soil holds above 50°F.
What growing zone is Cass County, IA for Zucchini?
Cass County sits in USDA Zone 5b. Zucchini grows reliably in zones 3a through 11b, so it's a good fit here.
Can Zucchini grow in Cass County's climate?
Yes — Zucchini grows well in Cass County's temperate climate. Cass County averages a 167-day frost-free season, with last frost around April 25 and first frost around October 9.
Your Cass County Garden Planner — Free
A 22-page printable planner built for Cass County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.