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When to Plant Jostaberry in Ontonagon County, MI

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.

Ontonagon County, Michigan is in USDA Zone 4a. The average last spring frost is May 22 and the first fall frost is September 28, giving you a growing season of approximately 129 days.

At an elevation of 502 feet, Ontonagon County receives approximately 42 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80ยฐF, so choose short-season varieties of Jostaberry to ensure they mature before fall.

Ontonagon County, MI (Zone 4a) Short season
129 days
Last Spring Frost May 22
129 growing days
First Fall Frost September 28

Ontonagon County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: Jun 15
Recommended (50%) ✓ Fits season
Transplant: Jun 19
Safe Start (90%) ✓ Fits season
Transplant: Jul 4

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 Ontonagon County

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

Soil pH

Your soil pH (6.2โ€“7.2) is more alkaline than Jostaberry prefers (6.0โ€“6.5). Add sulfur or peat moss to lower pH.

Soil Texture

The silt loam soil in Ontonagon County is excellent for Jostaberry โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.1%) โ€” Jostaberry will thrive.

How to Plant Jostaberry

48"
Between Plants
72"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.4″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 โ€” 2" 0" โ„๏ธ Dormant
Feb โ€” 2.1" 0" โ„๏ธ Dormant
Mar โ€” 2.8" 0" โ„๏ธ Dormant
Apr โ€” 4.4" 0" โ„๏ธ Dormant
May 4.3" 4.8" 0" โœ… Rainfall sufficient
Jun 4.3" 5.2" 0" โœ… Rainfall sufficient
Jul 4.3" 4.3" 0" โœ… Rainfall sufficient
Aug 4.3" 4.2" 0.1" ๐Ÿ’ง Light watering
Sep 4.3" 3.5" 0.8" ๐Ÿ’ง Light watering
Oct โ€” 3.6" 0" โ„๏ธ Dormant
Nov โ€” 2.6" 0" โ„๏ธ Dormant
Dec โ€” 2.4" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in Ontonagon County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~9,125 GDD — county provides 1,290 GDD May not mature

Jostaberry Planting Timeline โ€” Ontonagon County, MI

Jostaberry Planting Calendar

Activity When Date Range
Transplant Outdoors June 19 Jun 19 โ€“ Jul 3

ยท 48" apart ยท Rows 72" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May โ€”
June Transplant Outdoors
July Transplant Outdoors
August โ€”
September โ€”
October โ€”
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Partial Shade (3-6 hours)

๐Ÿ’ง Water

1"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

730โ€“1095 days

๐Ÿงช Soil pH

Needs 6โ€“6.5 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 4a

๐Ÿ“† Growing Season

129 days in Ontonagon County

Growing Tips for Jostaberry in Ontonagon County

Direct sow Jostaberry outdoors after May 22 in Ontonagon County when soil has warmed and frost danger has passed.

Your 129.0-day growing season in Ontonagon 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 Ontonagon County, MI?

Ontonagon County is in Zone 4a with an average last frost of May 22. Plan your Jostaberry planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Ontonagon County, MI?

Ontonagon County, Michigan is in USDA Hardiness Zone 4a. The average last spring frost is May 22 and first fall frost is September 28.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Ontonagon County gardeners in Zone 4a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Ontonagon County, MI. Local conditions may vary. Last updated: April 2026.