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When to plant Zinnia in Morrison County, MN

For Morrison County, gardeners: plant Zinnia May 18 through June 8 once soil reads 50°F.

When to Plant Zinnia in Morrison County, MN

Morrison County, Minnesota Zone 4a June

June in Morrison County, Minnesota — your action list

June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Morrison County, Minnesota.

Avg. last frost May 4
Avg. first frost October 6
Soil temp (4") 66°F
Watering Low
Pest pressure High
Daylight 15.5 hrs
  1. Fire up the seed-starting tray: zinnia

    Your window is short. These crops want several weeks of indoor growth before they go outside.

Coming up in July — start thinking about
  • 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.

Morrison County, Minnesota is in USDA Zone 4a. The average last spring frost is May 4 and the first fall frost is October 6, giving you a growing season of approximately 155 days.

At an elevation of 1,070 feet, Morrison County receives approximately 40 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°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
Morrison County, MN (Zone 4a) Moderate season
155 days
Last Spring Frost May 4
155 growing days
First Fall Frost October 6

Morrison County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-7.1

Drainage

Well Drained

Zinnia Planting Risk Windows

Early Start (70% safe) ✓ Fits season (3 days to spare)
Start indoors: Mar 30 Transplant: May 11 🌸 Bloom: Jul 20 – Sep 28
Recommended (50%) ✓ Fits season (1 days to spare)
Start indoors: Apr 6 Transplant: May 18 🌸 Bloom: Jul 27 – Oct 5
Safe Start (90%) ✗ May not fit
Start indoors: Apr 22 Transplant: Jun 3 🌸 Bloom: Aug 12 – Oct 21

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 Morrison County

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

Soil pH

Your soil pH (5.7–7.1) is within Zinnia's preferred range (5.5–7.5).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.8%) — Zinnia will thrive.

How to Plant Zinnia

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

Succession Planting Zinnia

2
successive plantings in your 155-day season

Sow every 6.9 weeks. Last sowing by Jul 28 to harvest before frost.

Zinnia Water Budget

Plant needs
0.5″/week
Rainfall provides
1.1″/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 1.4" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 3.8" 0" ❄️ Dormant
May 2.2" 5" 0" ✅ Rainfall sufficient
Jun 2.2" 5.5" 0" ✅ Rainfall sufficient
Jul 2.2" 4" 0" ✅ Rainfall sufficient
Aug 2.2" 4.6" 0" ✅ Rainfall sufficient
Sep 2.2" 3.6" 0" ✅ Rainfall sufficient
Oct 2.2" 3.1" 0" ✅ Rainfall sufficient
Nov 2.7" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Morrison 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 ~650 GDD — county provides 1,550 GDD Excellent fit

Zinnia Planting Timeline — Morrison County, MN

Zinnia Planting Calendar

Activity When Date Range
Start Indoors April 6 Apr 6 – Apr 20
Transplant Outdoors May 18 May 18 – Jun 1
Direct Sow May 18 May 18 – Jun 8
Bloom July 27 Jul 27 – Oct 5

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

Month-by-Month Timeline

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

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 4a

📆 Growing Season

155 days in Morrison County

Growing Tips for Zinnia in Morrison County

Direct sow Zinnia outdoors after May 04 in Morrison 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.

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 Morrison County, MN?

Morrison County is in Zone 4a with an average last frost of May 4. Plan your Zinnia planting based on this frost date — see the calendar above for exact timing.

What planting zone is Morrison County, MN?

Morrison County, Minnesota is in USDA Hardiness Zone 4a. The average last spring frost is May 4 and first fall frost is October 6.

When should I plant Zinnia in Morrison County, MN?

In Morrison County, MN, plant Zinnia after the last frost (around May 4) and before the first frost (around October 6). Best results when soil holds above 50°F.

What growing zone is Morrison County, MN for Zinnia?

Morrison County sits in USDA Zone 4a. Zinnia grows reliably in zones 3a through 11b, so it's a good fit here.

Can Zinnia grow in Morrison County's climate?

Yes — Zinnia grows well in Morrison County's temperate climate. Morrison County averages a 155-day frost-free season, with last frost around May 4 and first frost around October 6.

🌱

Your Morrison County Garden Planner — Free

A 22-page printable planner built for Morrison County (Zone 4a). 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 Morrison County, MN. Local conditions may vary. Last updated: June 2026.

Sources & credits

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