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When to Plant Jostaberry in Mason County, MI

Mason County, Michigan Zone 6a May

May in the garden — Mason County, Michigan

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

Avg. last frost May 15
Avg. first frost October 7
Soil temp (4") 55°F
Watering Moderate
Pest pressure Low
Daylight 14.6 hrs
Looking ahead to June
  • Transplants going out: jostaberry

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Jostaberry is a thornless hybrid of black currant and gooseberry, producing medium-sized, dark berries with a complex, tart-sweet flavor. It is vigorous and disease-resistant.

Mason County, Michigan is in USDA Zone 6a. The average last spring frost is May 15 and the first fall frost is October 7, giving you a growing season of approximately 145 days.

At an elevation of 1,318 feet, Mason County receives approximately 34.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Jostaberry during the growing season.

Mason County, MI (Zone 6a) Short season
145 days
Last Spring Frost May 15
145 growing days
First Fall Frost October 7
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Mason County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: May 29
Recommended (50%) ✓ Fits season
Transplant: Jun 5
Safe Start (90%) ✓ Fits season
Transplant: Jun 19

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 Mason County

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

Soil pH

Your soil pH (6.0–7.3) is more alkaline than Jostaberry prefers (6.0–6.5). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.5%) — Jostaberry will thrive.

How to Plant Jostaberry

48"
Between Plants
72"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
Watering frequency Only during dry spells
Season total 5 gal / 100 sq ft

Monthly Watering Guide for Jostaberry

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

Month Jostaberry Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 3.1" 0" ❄️ Dormant
May 4.3" 3.3" 1" 💧 Light watering
Jun 4.3" 4.5" 0" ✅ Rainfall sufficient
Jul 4.3" 4.1" 0.2" 💧 Light watering
Aug 4.3" 3.9" 0.4" 💧 Light watering
Sep 4.3" 3.3" 1" 💧 Light watering
Oct 4.3" 2.9" 1.4" 💧 Light watering
Nov 2.1" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

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

Jostaberry 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.

Jostaberry needs ~12,547 GDD — county provides 1,993 GDD May not mature

Jostaberry Planting Timeline — Mason County, MI

Jostaberry Planting Calendar

Activity When Date Range
Transplant Outdoors June 5 Jun 5 – Jun 19

· 48" apart · Rows 72" 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

Partial Shade (3-6 hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

730–1095 days

🧪 Soil pH

Needs 6–6.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6a

📆 Growing Season

145 days in Mason County

Growing Tips for Jostaberry in Mason County

Direct sow Jostaberry outdoors after May 15 in Mason County when soil has warmed and frost danger has passed.

Your 145.0-day growing season in Mason County is tight for Jostaberry (730.0-1095.0 days to maturity). Start indoors and choose early-maturing varieties.

General growing tips

Plant in rich, well-drained soil. No special pruning required beyond removing old wood. Self-fertile but yields improve with a second bush. Berries ripen midsummer.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Jostaberry in Mason County, MI?

Mason County is in Zone 6a with an average last frost of May 15. Plan your Jostaberry planting based on this frost date — see the calendar above for exact timing.

What planting zone is Mason County, MI?

Mason County, Michigan is in USDA Hardiness Zone 6a. The average last spring frost is May 15 and first fall frost is October 7.

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Your Mason County Garden Planner — Free

A 24-page printable planner built for Mason County (Zone 6a). 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 Mason 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.