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When to Plant Raspberries in Phillips County, MT

Raspberries are beloved bramble fruits producing sweet, delicate berries in red, golden, black, and purple varieties. They spread by underground runners and are very productive.

Phillips County, Montana is in USDA Zone 4a. The average last spring frost is May 18 and the first fall frost is September 21, giving you a growing season of approximately 126 days.

At an elevation of 6,886 feet, Phillips County receives approximately 19 inches of rainfall annually with predominantly loam soil. Summer highs average 80ยฐF, so choose short-season varieties of Raspberries to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Raspberries successfully. Mulch heavily to conserve soil moisture.

Phillips County, MT (Zone 4a) Short season
126 days
Last Spring Frost May 18
126 growing days
First Fall Frost September 21

Phillips County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: Jun 9
Recommended (50%) ✓ Fits season
Transplant: Jun 15
Safe Start (90%) ✓ Fits season
Transplant: Jun 28

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 Phillips County

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

Soil pH

Your soil pH (6.7โ€“7.6) is more alkaline than Raspberries prefers (5.5โ€“6.5). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Raspberries.

How to Plant Raspberries

24"
Between Plants
72"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.6″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 493 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Monthly Watering Guide for Raspberries

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

Month Raspberries Needs Rainfall You Supplement Action
Jan โ€” 1.4" 0" โ„๏ธ Dormant
Feb โ€” 1" 0" โ„๏ธ Dormant
Mar โ€” 1.6" 0" โ„๏ธ Dormant
Apr โ€” 1.9" 0" โ„๏ธ Dormant
May 4.3" 2.4" 1.9" ๐Ÿ’ง Light watering
Jun 4.3" 1.4" 2.9" ๐Ÿšฟ Regular watering
Jul 4.3" 1.6" 2.7" ๐Ÿšฟ Regular watering
Aug 4.3" 2" 2.3" ๐Ÿšฟ Regular watering
Sep 4.3" 1.4" 2.9" ๐Ÿšฟ Regular watering
Oct โ€” 1.8" 0" โ„๏ธ Dormant
Nov โ€” 1.3" 0" โ„๏ธ Dormant
Dec โ€” 1.1" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in Phillips County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Raspberries 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.

Raspberries needs ~5,475 GDD — county provides 1,260 GDD May not mature

Raspberries Planting Timeline โ€” Phillips County, MT

Raspberries Planting Calendar

Activity When Date Range
Transplant Outdoors June 15 Jun 15 โ€“ Jun 29

ยท 24" apart ยท Rows 72" apart

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

365โ€“730 days

๐Ÿงช Soil pH

Needs 5.5โ€“6.5 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 4a

๐Ÿ“† Growing Season

126 days in Phillips County

Growing Tips for Raspberries in Phillips County

Direct sow Raspberries outdoors after May 18 in Phillips County when soil has warmed and frost danger has passed.

Your 126.0-day growing season in Phillips County is tight for Raspberries (365.0-730.0 days to maturity). Start indoors and choose early-maturing varieties.

Phillips County receives only 19" of rain annually. Raspberries needs consistent moisture โ€” install drip irrigation or water deeply 2-3 times per week.

General growing tips

Provide a trellis for support. Prune summer-bearing types by removing spent canes after harvest. For ever-bearing types, mow all canes in late winter for a single fall crop.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes
  • Tomatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Raspberries in Phillips County, MT?

Phillips County is in Zone 4a with an average last frost of May 18. Plan your Raspberries planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Phillips County, MT?

Phillips County, Montana is in USDA Hardiness Zone 4a. The average last spring frost is May 18 and first fall frost is September 21.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Phillips 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 Phillips County, MT. Local conditions may vary. Last updated: April 2026.