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When to Plant Mulberries in Delta County, MI

Delta County, Michigan Zone 5a May

May to-do list for Delta County, Michigan

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Delta County, Michigan.

Avg. last frost May 12
Avg. first frost October 14
Soil temp (4") 56°F
Watering Low
Pest pressure Low
Daylight 14.7 hrs
Coming up in June — start thinking about
  • Transplants going out: mulberries

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Mulberries are fast-growing, long-lived trees that produce abundant sweet-tart berries over an extended harvest period. The berries resemble elongated blackberries.

Delta County, Michigan is in USDA Zone 5a. The average last spring frost is May 12 and the first fall frost is October 14, giving you a growing season of approximately 155 days.

At an elevation of 921 feet, Delta County receives approximately 41.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Mulberries to ensure they mature before fall.

Delta County, MI (Zone 5a) Moderate season
155 days
Last Spring Frost May 12
155 growing days
First Fall Frost October 14
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Delta County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: May 27
Recommended (50%) ✓ Fits season
Transplant: Jun 2
Safe Start (90%) ✓ Fits season
Transplant: Jun 16

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 Delta County

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

Soil pH

Your soil pH (6.2–6.8) is within Mulberries's preferred range (5.5–7.0).

Soil Texture

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

Organic Matter

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

How to Plant Mulberries

120"
Between Plants
144"
Between Rows

Plant Water Budget

Plant needs
1.0″/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 Mulberries

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

Month Mulberries Needs Rainfall You Supplement Action
Jan 1.8" 0" ❄️ Dormant
Feb 2" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 3.6" 0" ❄️ Dormant
May 4.3" 5.3" 0" ✅ Rainfall sufficient
Jun 4.3" 4.8" 0" ✅ Rainfall sufficient
Jul 4.3" 4.8" 0" ✅ Rainfall sufficient
Aug 4.3" 3.8" 0.5" 💧 Light watering
Sep 4.3" 3.6" 0.7" 💧 Light watering
Oct 4.3" 3.3" 1" 💧 Light watering
Nov 3.2" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

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

Mulberries 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.

Mulberries needs ~15,649 GDD — county provides 1,898 GDD May not mature

Mulberries Planting Timeline — Delta County, MI

Mulberries Planting Calendar

Activity When Date Range
Transplant Outdoors June 2 Jun 2 – Jun 16

· 120" apart · Rows 144" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May
June Transplant Outdoors
July
August
September
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

730–1825 days

🧪 Soil pH

Needs 5.5–7 · Your soil: ideal

🗺️ USDA Zone

Zone 5a

📆 Growing Season

155 days in Delta County

Growing Tips for Mulberries in Delta County

Direct sow Mulberries outdoors after May 12 in Delta County when soil has warmed and frost danger has passed.

Your 155.0-day growing season in Delta County is tight for Mulberries (730.0-1825.0 days to maturity). Start indoors and choose early-maturing varieties.

General growing tips

Plant away from driveways and patios as fallen berries stain. Minimal pruning is needed. Harvest by shaking branches over a tarp. Birds love mulberries so plant extra.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Mulberries in Delta County, MI?

Delta County is in Zone 5a with an average last frost of May 12. Plan your Mulberries planting based on this frost date — see the calendar above for exact timing.

What planting zone is Delta County, MI?

Delta County, Michigan is in USDA Hardiness Zone 5a. The average last spring frost is May 12 and first fall frost is October 14.

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Your Delta County Garden Planner — Free

A 24-page printable planner built for Delta County (Zone 5a). 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 Delta County, MI. Local conditions may vary. Last updated: May 2026.

Sources & credits

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