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When to plant Begonias in Mower County, MN

Mower County sits in cold Zone 4b. Plant Begonias May 5–May 19 for the single annual harvest; the October 7 first frost closes the window.

When to Plant Begonias in Mower County, MN

Mower County, Minnesota Zone 4b July

Your July planting checklist for Mower County, Minnesota

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

Avg. last frost April 28
Avg. first frost October 7
Soil temp (4") 71°F
Watering Moderate
Pest pressure High
Daylight 14.9 hrs
  1. Start begonias under lights

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

  2. Basket week: begonias

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

Before August arrives, get these ready
  • First harvests: begonias

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Wax begonias (Begonia × semperflorens) are the workhorse shade bedding plant of American horticulture, offering continuous bloom from transplant to hard frost. Bronze or green-leaved varieties perform well from deep shade to full sun (in northern zones) and tolerate summer humidity better than most cool- season flowers. A staple of mass plantings, containers, and window boxes.

Mower County, Minnesota is in USDA Zone 4b. The average last spring frost is April 28 and the first fall frost is October 7, giving you a growing season of approximately 162 days.

At an elevation of 577 feet, Mower County receives approximately 33 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82°F, so choose short-season varieties of Begonias to ensure they mature before fall.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant
Mower County, MN (Zone 4b) Moderate season
162 days
Last Spring Frost April 28
162 growing days
First Fall Frost October 7

Mower County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.7

Drainage

Well Drained

Begonias Planting Risk Windows

Early Start (70% safe) ✓ Fits season (12 days to spare)
Start indoors: Feb 6 Transplant: May 1 🌸 Bloom: Jul 10 – Sep 18
Recommended (50%) ✓ Fits season (15 days to spare)
Start indoors: Feb 10 Transplant: May 5 🌸 Bloom: Jul 14 – Sep 22
Safe Start (90%) ✓ Fits season (8 days to spare)
Start indoors: Feb 26 Transplant: May 21 🌸 Bloom: Jul 30 – Oct 8

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 Mower County

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

Soil pH

Your soil pH (6.3–6.7) overlaps with Begonias's range (5.5–6.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.6%) — Begonias will thrive.

How to Plant Begonias

8"
Between Plants
10"
Between Rows

Succession Planting Begonias

2
successive plantings in your 162-day season

Sow every 8 weeks. Last sowing by Jul 09 to harvest before frost.

Begonias Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 208 gal / 100 sq ft

Monthly Watering Guide for Begonias

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

Month Begonias Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 4.3" 3.7" 0.6" 💧 Light watering
May 4.3" 3.4" 0.9" 💧 Light watering
Jun 4.3" 3.9" 0.4" 💧 Light watering
Jul 4.3" 3.3" 1" 💧 Light watering
Aug 4.3" 3.6" 0.7" 💧 Light watering
Sep 4.3" 2.8" 1.5" 💧 Light watering
Oct 4.3" 2.4" 1.9" 💧 Light watering
Nov 2.5" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

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

Begonias 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.

Begonias needs ~920 GDD — county provides 1,863 GDD Excellent fit

Begonias Planting Timeline — Mower County, MN

Begonias Planting Calendar

Activity When Date Range
Start Indoors February 10 Feb 10 – Feb 24
Transplant Outdoors May 5 May 5 – May 19
Bloom July 14 Jul 14 – Sep 22

· 8" apart · Rows 10" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 5.5–6.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 4b

📆 Growing Season

162 days in Mower County

Growing Tips for Begonias in Mower County

Direct sow Begonias outdoors after April 28 in Mower County when soil has warmed and frost danger has passed.

General growing tips

Start seeds indoors 10–12 weeks before last frost — seed is dust-fine; surface-sow on moist mix under lights, do not cover. Bottom heat (70–75°F) speeds germination. Transplant after frost; begonias are not direct-sown in practice. Pinch seedlings once for branching. Keep soil evenly moist; avoid waterlogged conditions. Bronze-leaf types tolerate more sun; green- leaf types prefer shade to part-sun.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Begonias in Mower County, MN?

Mower County is in Zone 4b with an average last frost of April 28. Plan your Begonias planting based on this frost date — see the calendar above for exact timing.

What planting zone is Mower County, MN?

Mower County, Minnesota is in USDA Hardiness Zone 4b. The average last spring frost is April 28 and first fall frost is October 7.

When should I plant Begonias in Mower County, MN?

In Mower County, MN, plant Begonias after the last frost (around April 28) and before the first frost (around October 7). Best results when soil holds above 50°F.

What growing zone is Mower County, MN for Begonias?

Mower County sits in USDA Zone 4b. Begonias grows reliably in zones 2a through 11b, so it's a good fit here.

Can Begonias grow in Mower County's climate?

Yes — Begonias grows well in Mower County's temperate climate. Mower County averages a 162-day frost-free season, with last frost around April 28 and first frost around October 7.

🌱

Your Mower County Garden Planner — Free

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

Sources & credits

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