Blog

When to plant Zinnia in Leavenworth County County,

Spring Zinnia in Leavenworth County County goes in April 14–May 5, once nighttime temps stop dipping near freezing.

When to Plant Zinnia in Leavenworth County, KS

Leavenworth County, Kansas Zone 6b June

Your June gardening checklist

Welcome to June in Zone 6b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 14
Avg. first frost October 24
Soil temp (4") 73°F
Watering Moderate
Pest pressure High
Daylight 14.7 hrs
  1. Harvest zinnia as they ripen

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

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

Instant PDF download. No spam, unsubscribe any time.

Zinnia (Zinnia elegans) is a fast-growing, heat-loving annual that produces bold, dahlia-like blooms from early summer until hard frost. One of the easiest flowers to grow from direct-sown seed, zinnias thrive in hot, dry conditions and are magnets for butterflies and beneficial insects. They make excellent companion plants alongside marigolds in the vegetable garden.

Leavenworth County, Kansas is in USDA Zone 6b. The average last spring frost is April 14 and the first fall frost is October 24, giving you a growing season of approximately 193 days.

At an elevation of 693 feet, Leavenworth County receives approximately 20.3 inches of rainfall annually with predominantly loam soil. Summer highs average 88°F, providing good warmth for Zinnia during the growing season.

Annual Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Leavenworth County, KS (Zone 6b) Moderate season
193 days
Last Spring Frost April 14
193 growing days
First Fall Frost October 24

Leavenworth County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.7

Drainage

Well Drained

Zinnia Planting Risk Windows

Early Start (70% safe) ✓ Fits season (24 days to spare)
Start indoors: Mar 10 Transplant: Apr 7 🌸 Bloom: Jun 16 – Sep 22
Recommended (50%) ✓ Fits season (25 days to spare)
Start indoors: Mar 17 Transplant: Apr 14 🌸 Bloom: Jun 23 – Sep 29
Safe Start (90%) ✓ Fits season (27 days to spare)
Start indoors: Mar 30 Transplant: Apr 27 🌸 Bloom: Jul 6 – Oct 12

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 Leavenworth County

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

Soil pH

Your soil pH (6.6–7.7) overlaps with Zinnia's range (5.5–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.3%) — Zinnia will thrive.

How to Plant Zinnia

0.3"
Planting Depth
12"
Between Plants
18"
Between Rows

Succession Planting Zinnia

3
successive plantings in your 193-day season

Sow every 6.9 weeks. Last sowing by Aug 15 to harvest before frost.

Zinnia Water Budget

Plant needs
0.5″/week
Rainfall provides
0.4″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 120 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Zinnia

Zinnia needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Zinnia Needs Rainfall You Supplement Action
Jan 0.5" 0" ❄️ Dormant
Feb 0.7" 0" ❄️ Dormant
Mar 1.2" 0" ❄️ Dormant
Apr 2.2" 2" 0.2" 💧 Light watering
May 2.2" 3.2" 0" ✅ Rainfall sufficient
Jun 2.2" 3" 0" ✅ Rainfall sufficient
Jul 2.2" 2.8" 0" ✅ Rainfall sufficient
Aug 2.2" 2.4" 0" ✅ Rainfall sufficient
Sep 2.2" 1.9" 0.3" 💧 Light watering
Oct 2.2" 1.3" 0.9" 💧 Light watering
Nov 0.7" 0" ❄️ Dormant
Dec 0.6" 0" ❄️ Dormant

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

Zinnia 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.

Zinnia needs ~1,040 GDD — county provides 3,088 GDD Excellent fit

Zinnia Planting Timeline — Leavenworth County, KS

Zinnia Planting Calendar

Activity When Date Range
Start Indoors March 17 Mar 17 – Mar 31
Transplant Outdoors April 14 Apr 14 – Apr 28
Direct Sow April 14 Apr 14 – May 5
Bloom June 23 Jun 23 – Sep 29

Plant 0.3" deep · 12" apart · Rows 18" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Only during dry spells

📅 Days to Maturity

60–70 days

🧪 Soil pH

Needs 5.5–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

193 days in Leavenworth County

Growing Tips for Zinnia in Leavenworth County

Direct sow Zinnia outdoors after April 14 in Leavenworth County when soil has warmed and frost danger has passed.

Common pests for Zinnia in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

Leavenworth County receives only 20" of rain annually. Zinnia needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct-sow after last frost when soil reaches 60°F; seeds germinate in 5-7 days. In zones 3-5 a brief indoor start (4 weeks) is worthwhile but transplant carefully — zinnias dislike root disturbance. Deadhead frequently to extend bloom. Excellent cut flower; harvesting regularly encourages branching. Avoid overhead watering to reduce powdery mildew.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Zinnia in Leavenworth County, KS?

Leavenworth County is in Zone 6b with an average last frost of April 14. Plan your Zinnia planting based on this frost date — see the calendar above for exact timing.

What planting zone is Leavenworth County, KS?

Leavenworth County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 14 and first fall frost is October 24.

When should I plant Zinnia in Leavenworth County County, ?

In Leavenworth County County, , plant Zinnia after the last frost (around April 14) and before the first frost (around October 24). Best results when soil holds above 50°F.

What growing zone is Leavenworth County County, for Zinnia?

Leavenworth County County sits in USDA Zone 6b. Zinnia grows reliably in zones 3a through 11b, so it's a good fit here.

Can Zinnia grow in Leavenworth County County's climate?

Yes — Zinnia grows well in Leavenworth County County's temperate climate. Leavenworth County County averages a 193-day frost-free season, with last frost around April 14 and first frost around October 24.

🌱

Your Leavenworth County Garden Planner — Free

A 22-page printable planner built for Leavenworth 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.

Instant PDF download. No spam, unsubscribe any time.

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

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.