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When to plant Petunia in Grant County County,

Grant County County's 179-day season only supports one Petunia planting per year. Sow between April 28 and May 12 for the best chance at full maturity before October 17.

When to Plant Petunia in Grant County, KS

Grant County, Kansas Zone 6b June

June in Grant County, Kansas — your action list

Your garden in Grant County, Kansas is working on a schedule, even when you're not. Here's where you should be this June.

Avg. last frost April 21
Avg. first frost October 17
Soil temp (4") 74°F
Watering High
Pest pressure High
Daylight 14.6 hrs
  1. Sow petunia in trays indoors

    You're about 18 weeks out from your last frost — the perfect window to get these germinating indoors.

To set up a strong July, finish these tasks
  • First harvests: petunia

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Petunias (Petunia x hybrida) are warm-season tender annuals prized for their prolific, trumpet-shaped blooms in nearly every color. They perform from hanging baskets to garden borders and bloom continuously from late spring until frost, provided spent flowers are removed regularly.

Grant County, Kansas is in USDA Zone 6b. The average last spring frost is April 21 and the first fall frost is October 17, giving you a growing season of approximately 179 days.

At an elevation of 1,096 feet, Grant County receives approximately 25.2 inches of rainfall annually with predominantly loam soil. Summer highs average 85°F, providing good warmth for Petunia during the growing season.

Annual Blooms in Summer Pollinator-friendly Fragrant
Grant County, KS (Zone 6b) Moderate season
179 days
Last Spring Frost April 21
179 growing days
First Fall Frost October 17

Grant County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.7

Drainage

Well Drained

Petunia Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Feb 19 Transplant: Apr 23 🌸 Bloom: Jul 2 – Oct 15
Recommended (50%) ✗ May not fit
Start indoors: Feb 24 Transplant: Apr 28 🌸 Bloom: Jul 7 – Oct 20
Safe Start (90%) ✗ May not fit
Start indoors: Mar 9 Transplant: May 11 🌸 Bloom: Jul 20 – Nov 2

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 Grant County

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

Soil pH

Your soil pH (6.4–7.7) is more alkaline than Petunia prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Grant County is excellent for Petunia — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.1%) — Petunia will thrive.

How to Plant Petunia

12"
Between Plants
12"
Between Rows

Succession Planting Petunia

2
successive plantings in your 179-day season

Sow every 8 weeks. Last sowing by Jul 19 to harvest before frost.

Petunia Water Budget

Plant needs
1.0″/week
Rainfall provides
0.6″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 781 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Petunia

Petunia needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Petunia Needs Rainfall You Supplement Action
Jan 1.8" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 4.3" 3" 1.3" 💧 Light watering
May 4.3" 2.8" 1.5" 💧 Light watering
Jun 4.3" 1.9" 2.4" 🚿 Regular watering
Jul 4.3" 2" 2.3" 🚿 Regular watering
Aug 4.3" 2.7" 1.6" 💧 Light watering
Sep 4.3" 2.4" 1.9" 💧 Light watering
Oct 4.3" 2.1" 2.2" 🚿 Regular watering
Nov 1.6" 0" ❄️ Dormant
Dec 1.5" 0" ❄️ Dormant

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

Petunia 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.

Petunia needs ~1,100 GDD — county provides 2,461 GDD Excellent fit

Petunia Planting Timeline — Grant County, KS

Petunia Planting Calendar

Activity When Date Range
Start Indoors February 24 Feb 24 – Mar 10
Transplant Outdoors April 28 Apr 28 – May 12
Bloom July 7 Jul 7 – Oct 20

· 12" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6b

📆 Growing Season

179 days in Grant County

Growing Tips for Petunia in Grant County

Direct sow Petunia outdoors after April 21 in Grant County when soil has warmed and frost danger has passed.

Common pests for Petunia 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; seeds need light to germinate — press onto moist mix surface, do not cover. Transplant after last frost once nights stay above 50°F. Pinch back leggy plants mid-summer to encourage bushy re-bloom. Wave/spreading types tolerate light shade but bloom less. Feed every 2 weeks with balanced fertilizer once established.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Petunia in Grant County, KS?

Grant County is in Zone 6b with an average last frost of April 21. Plan your Petunia planting based on this frost date — see the calendar above for exact timing.

What planting zone is Grant County, KS?

Grant County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 21 and first fall frost is October 17.

When should I plant Petunia in Grant County County, ?

In Grant County County, , plant Petunia after the last frost (around April 21) and before the first frost (around October 17). Best results when soil holds above 50°F.

What growing zone is Grant County County, for Petunia?

Grant County County sits in USDA Zone 6b. Petunia grows reliably in zones 2a through 11b, so it's a good fit here.

Can Petunia grow in Grant County County's climate?

Yes — Petunia grows well in Grant County County's temperate climate. Grant County County averages a 179-day frost-free season, with last frost around April 21 and first frost around October 17.

🌱

Your Grant County Garden Planner — Free

A 22-page printable planner built for Grant County (Zone 6b). 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 Grant County, KS. Local conditions may vary. Last updated: June 2026.

Sources & credits

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