When to plant Peppers in Union County, IA
For Peppers in Union County, the safe spring window opens around April 30 and closes around May 21. Last expected frost is April 23, first fall frost October 11, giving a 171-day growing season.
When to Plant Peppers in Union County, IA
July in the garden — Union 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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Fire up the seed-starting tray: peppers
Label every cell. You will absolutely forget which is which otherwise.
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Bring in the peppers
Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.
Looking ahead to August
- First harvests: peppers
Sweet peppers are warm-season crops producing fruits in a rainbow of colors. They turn from green to red, yellow, or orange as they ripen, increasing in sweetness.
Union County, Iowa is in USDA Zone 5b. The average last spring frost is April 23 and the first fall frost is October 11, giving you a growing season of approximately 171 days.
At an elevation of 1,311 feet, Union County receives approximately 39 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Peppers to ensure they mature before fall.
Union County Soil Profile
Soil Type
Silt Loam
Soil pH
6.3-7.3
Drainage
Well Drained
Peppers 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 Union County
How your county's soil matches Peppers's growing requirements.
Soil pH
Your soil pH (6.3–7.3) overlaps with Peppers's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Union County is excellent for Peppers — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.8%) — Peppers will thrive.
How to Plant Peppers
Succession Planting Peppers
Sow every 6.9 weeks. Last sowing by Jul 13 to harvest before frost.
Peppers Water Budget
Monthly Watering Guide for Peppers
Peppers 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 | Peppers Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.8" | 0" | ❄️ Dormant |
| Feb | — | 1.8" | 0" | ❄️ Dormant |
| Mar | — | 2.7" | 0" | ❄️ Dormant |
| Apr | 4.8" | 4.1" | 0.7" | 💧 Light watering |
| May | 4.8" | 4.1" | 0.7" | 💧 Light watering |
| Jun | 4.8" | 4.7" | 0.1" | 💧 Light watering |
| Jul | 4.8" | 4.2" | 0.6" | 💧 Light watering |
| Aug | 4.8" | 4" | 0.8" | 💧 Light watering |
| Sep | 4.8" | 3.4" | 1.4" | 💧 Light watering |
| Oct | 4.8" | 3" | 1.8" | 💧 Light watering |
| Nov | — | 2.8" | 0" | ❄️ Dormant |
| Dec | — | 2.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Union County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Peppers 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.
Peppers Planting Timeline — Union County, IA
Peppers Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 12 | Feb 12 – Feb 26 |
| Transplant Outdoors | May 7 | May 7 – May 21 |
| Direct Sow | April 30 | Apr 30 – May 21 |
| Harvest | July 9 | Jul 9 – Sep 17 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | — |
| April | Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.1"/week · Only during dry spells
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 5b
📆 Growing Season
171 days in Union County
Growing Tips for Peppers in Union County
Direct sow Peppers outdoors after April 23 in Union County when soil has warmed and frost danger has passed.
Common pests for Peppers in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.
General growing tips
Start seeds indoors 8-10 weeks before last frost. Transplant when nighttime temperatures stay above 55F. Avoid high-nitrogen fertilizers which promote leaves over fruit.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Isolate 300 ft for purity. Hot and sweet peppers can cross-pollinate.
Peppers in Other Locations
Frequently Asked Questions
When should I plant Peppers in Union County, IA?
Union County is in Zone 5b with an average last frost of April 23. Plan your Peppers planting based on this frost date — see the calendar above for exact timing.
What planting zone is Union County, IA?
Union County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 23 and first fall frost is October 11.
When should I plant Peppers in Union County, IA?
In Union County, IA, plant Peppers after the last frost (around April 23) and before the first frost (around October 11). Best results when soil holds above 50°F.
What growing zone is Union County, IA for Peppers?
Union County sits in USDA Zone 5b. Peppers grows reliably in zones 3a through 11b, so it's a good fit here.
Can Peppers grow in Union County's climate?
Yes — Peppers grows well in Union County's temperate climate. Union County averages a 171-day frost-free season, with last frost around April 23 and first frost around October 11.
Your Union County Garden Planner — Free
A 22-page printable planner built for Union 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.