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When to Plant Zinnia in Seward County, NE

Seward County, Nebraska Zone 5b June

June to-do list for Seward County, Nebraska

June is a pivotal month for Seward County, Nebraska gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 21
Avg. first frost October 13
Soil temp (4") 71°F
Watering Low
Pest pressure High
Daylight 14.9 hrs
To set up a strong July, finish these tasks
  • First harvests: zinnia

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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.

Seward County, Nebraska is in USDA Zone 5b. The average last spring frost is April 21 and the first fall frost is October 13, giving you a growing season of approximately 175 days.

At an elevation of 527 feet, Seward County receives approximately 24.2 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Zinnia to ensure they mature before fall.

Annual Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Seward County, NE (Zone 5b) Moderate season
175 days
Last Spring Frost April 21
175 growing days
First Fall Frost October 13
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Seward County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.2

Drainage

Well Drained

Zinnia Planting Risk Windows

Early Start (70% safe) ✓ Fits season (9 days to spare)
Start indoors: Mar 19 Transplant: Apr 23 🌸 Bloom: Jul 2 – Oct 1
Recommended (50%) ✓ Fits season (7 days to spare)
Start indoors: Mar 24 Transplant: Apr 28 🌸 Bloom: Jul 7 – Oct 6
Safe Start (90%) ✓ Fits season (10 days to spare)
Start indoors: Apr 4 Transplant: May 9 🌸 Bloom: Jul 18 – Oct 17

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 Seward County

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

Soil pH

Your soil pH (6.4–7.2) is within Zinnia's preferred range (5.5–7.5).

Soil Texture

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

Organic Matter

Organic matter is moderate (3.9%). Annual compost additions will help Zinnia.

How to Plant Zinnia

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

Succession Planting Zinnia

3
successive plantings in your 175-day season

Sow every 6.9 weeks. Last sowing by Aug 04 to harvest before frost.

Zinnia Water Budget

Plant needs
0.5″/week
Rainfall provides
0.6″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 0.6" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.4" 0" ❄️ Dormant
Apr 2.2" 2.8" 0" ✅ Rainfall sufficient
May 2.2" 3.7" 0" ✅ Rainfall sufficient
Jun 2.2" 4.2" 0" ✅ Rainfall sufficient
Jul 2.2" 3.1" 0" ✅ Rainfall sufficient
Aug 2.2" 2.5" 0" ✅ Rainfall sufficient
Sep 2.2" 2.3" 0" ✅ Rainfall sufficient
Oct 2.2" 1.3" 0.9" 💧 Light watering
Nov 0.8" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Seward 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 ~845 GDD — county provides 2,275 GDD Excellent fit

Zinnia Planting Timeline — Seward County, NE

Zinnia Planting Calendar

Activity When Date Range
Start Indoors March 24 Mar 24 – Apr 7
Transplant Outdoors April 28 Apr 28 – May 12
Direct Sow April 28 Apr 28 – May 19
Bloom July 7 Jul 7 – Oct 6

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

60–70 days

🧪 Soil pH

Needs 5.5–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 5b

📆 Growing Season

175 days in Seward County

Growing Tips for Zinnia in Seward County

Direct sow Zinnia outdoors after April 21 in Seward 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.

Seward County receives only 24" 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 Seward County, NE?

Seward County is in Zone 5b with an average last frost of April 21. Plan your Zinnia planting based on this frost date — see the calendar above for exact timing.

What planting zone is Seward County, NE?

Seward County, Nebraska is in USDA Hardiness Zone 5b. The average last spring frost is April 21 and first fall frost is October 13.

🌱

Your Seward County Garden Planner — Free

A 22-page printable planner built for Seward 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.

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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 Seward County, NE. 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.