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Phillips County, MT — Planting Guide

Phillips County, Montana Zone 3b July

Your July planting checklist for Phillips County, Montana

If you only do a handful of things in the garden this July, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 18
Avg. first frost September 21
Soil temp (4") 51°F
Watering High
Pest pressure High
Daylight 15.5 hrs
  1. Indoor seed-starting week for pole beans, tomatoes, and ageratum

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

  2. Collect carrots, green beans, and kale at their peak

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

August will be here before you know it — start on
  • Starting indoors: peppers, begonias, and geraniums
  • First harvests: carrots, cucumber, and green beans
  • Fall sowing: alliums, crocus, and daffodils

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Phillips County is in USDA Zone 3b. 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 ft, Phillips County receives approximately 19 in of rainfall annually. The predominant soil type is Loam.

Based on 31 years of NOAA climate station data, the last frost date here varies by 30 days year to year — ranging from May 1 in warm years to May 31 in cold years. The growing season is trending longer by about 2.47 days per decade. Phillips County scores 32/100 (Challenging) on the Microclimate Index.

🌡️ Zone

3b (-35°F to -30°F min)

❄️ Last Frost

May 18

🍂 First Frost

September 21

📅 Growing Season

126 days

⛰️ Elevation

6,886 ft

🌧️ Annual Rainfall

19 in

Phillips County, MT Short season
126 days
Last Spring Frost May 18
126 growing days
First Fall Frost September 21

Monthly Watering Calendar for Phillips County

When you'll need to water your garden — based on average monthly rainfall vs. the ~1 inch/week most gardens need.

Quick context: In humid climates, watering is usually about timing (morning, not evening, to prevent disease) more than volume. In dry climates, it's about depth (water deep, less often) more than frequency. Phillips County's 19" annual tells you which side you're on.

1"/wk 0" 1.3" 2.5" 3.8" 5" Jan 1.4" Feb 1" Mar 1.6" +2.4" Apr 1.9" +1.9" May 2.4" +2.9" Jun 1.4" +2.7" Jul 1.6" +2.3" Aug 2" +2.9" Sep 1.4" +2.5" Oct 1.8" Nov 1.3" Dec 1.1"
Rainfall sufficient Supplemental water needed Heavy watering required - - - 1"/week garden need
View detailed monthly data
MonthAvg RainfallRainy DaysExtra Water NeededWatering Effort
Jan 1.4 in 6 days None
Feb 1 in 5 days None
Mar 1.6 in 8 days None
Apr 1.9 in 7 days 2.4 in High
May 2.4 in 7 days 1.9 in High
Jun 1.4 in 4 days 2.9 in High
Jul 1.6 in 6 days 2.7 in High
Aug 2 in 6 days 2.3 in High
Sep 1.4 in 5 days 2.9 in High
Oct 1.8 in 5 days 2.5 in High
Nov 1.3 in 5 days None
Dec 1.1 in 7 days None

Annual total: 18.9 in. Water needs vary by crop — tomatoes need ~1.2"/week while herbs like rosemary need only 0.3"/week. Check individual plant pages for crop-specific water budgets that factor in your county's rainfall and soil drainage.

Phillips County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.6

Drainage

Well Drained

Frost Risk Probability

Based on 31 years of NOAA weather station data from 3 stations

Too early frost risk Safe to Plant May 18 → Sep 21 126 frost-free days Protect crops frost returns Apr May Jun Jul Aug Sep Oct Nov Safe: May 31 Protect by: Oct 5

Beginners: Plant frost-sensitive crops (tomatoes, peppers, squash) after the "Safe" date on the left. Harvest or cover them before the "Protect by" date on the right. Hardy crops (lettuce, peas, kale) can go in the yellow transition zones.

How to read this table: "Conservative" means you're safe from frost 9 out of 10 years — best for beginners and frost-sensitive crops. "Average year" is the typical date. "Aggressive" means only 1 in 10 years is that warm — experienced gardeners with frost protection can try these dates.

Planting Strategy Last Spring Frost First Fall Frost Frost-Free Days
Conservative (safest) May 31 Oct 5 127 days
Cautious May 21 Sep 27 129 days
Average year May 18 Sep 21 126 days
Optimistic May 12 Sep 13 124 days
Aggressive (risky) May 1 Sep 8 130 days
📊
How predictable are frost dates here?

Not very — frost dates can vary by ±30 days year-to-year. Use the "Conservative" row in the table below, and keep row covers handy for surprise late frosts.

🌱
Is the growing season changing?

Yes — growing seasons are getting longer here (about 2.5 days per decade). Spring is arriving earlier than it used to. Good news for gardeners.

Gardening Difficulty Score

32 Challenging
Frost Timing Risk
10.0/10
Drought Risk
5.5/10
Soil Difficulty
1.0/10
Altitude Challenge
10.0/10
Climate Shift
9.9/10
Rainfall Challenge
4.4/10

Phillips County has challenging growing conditions. Season extension and careful variety selection are essential.

Zone 3b Frost Countdown
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Loading...
Last Frost: May 18 First Frost: Sep 21

Local Gardening Help in Phillips County

Free expert help is closer than you think. Your county's cooperative extension office connects you with trained gardeners, soil testing labs, and local programs — all specific to Phillips County's climate and soil.

County Extension Office

Phillips County Montana State University Extension Extension Office

Phone: 406-994-3402

Visit Extension Office Website →

Extension offices are run by land-grant universities and funded by the USDA. Their advice is free, research-based, and tailored to your county's specific conditions.

Master Gardener Program

Free gardening help from trained volunteers

Master Gardeners are community volunteers who complete 40–60 hours of university horticultural training. They answer gardening questions, diagnose plant problems, and offer workshops — all free.

Find Master Gardeners in MT →

Many extension offices run a Master Gardener hotline where you can call or email with photos of plant problems for free diagnosis.

Soil Testing

Available through your extension office

Before amending your soil, get it tested. Your extension office offers soil testing (typically $10–$25) that tells you exact pH, nutrient levels, and amendment recommendations specific to what you want to grow.

Request a Soil Test →

Services Available in Phillips County

Soil testing Short-season gardening Pest identification
Finding local nurseries & garden centers in Phillips County

Why Buy Local

Local nurseries carry plants that are proven to grow in your area. Staff can give you advice specific to Phillips County's soil and climate that big-box stores can't. Plants from local growers are typically hardier because they're already acclimated to your zone.

How to Find Them

Search for "nurseries near Phillips County MT" or "garden center Phillips County" on Google Maps. Also check with your extension office — they often maintain lists of reputable local nurseries and plant sales.

Community gardens & gardening groups

Community gardens are a great way to learn from experienced gardeners in your area, especially if you're limited on space. Search "community garden Phillips County MT" or check your extension office and local parks department. Facebook groups like "Phillips County Gardeners" or "Montana Gardening" are also excellent for local advice and plant swaps.

What to Plant After Your Harvest

After your first crops finish, use the remaining frost-free days to grow a second round.

Show 1 more succession options
After Turnip (harvest ends Aug 3) 49 days until frost

Sunlight & Day Length in Phillips County

Monthly daylight hours and peak sun — critical for onion varieties, photoperiod-sensitive plants, and solar garden planning.

The practical takeaway: Plants use day length as their seasonal clock. Some crops flower when days lengthen (most flowers), some when days shorten (chrysanthemums, soybeans). Phillips County's curve is the timing layer beneath everything you grow.

Longest Day

15.9 hours

Summer solstice daylight

Shortest Day

8.1 hours

Winter solstice daylight

Peak Sun Hours

11.7 hr/day peak (summer)

Peak sun hours (green dashed line below) account for cloud cover — this is the usable direct sunlight your garden actually receives. Most vegetables need 6+ peak sun hours.

14hr 12hr 3h 7h 10h 14h 17h Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Daylight hours (sunrise to sunset) Peak sun hours (direct sunlight after cloud cover) ▪ Gold zone = long day (14+ hr) ▪ Blue zone = short day (<12 hr)

Onion tip: Your long summer days (14+ hours) support long-day onion varieties like Walla Walla, Sweet Spanish, and Ailsa Craig.

View detailed monthly data
MonthDaylight HoursPeak Sun HoursDay Length
January 8.6 hr 4.8 hr Short day
February 10 hr 5.5 hr Short day
March 11.6 hr 6.8 hr Short day
April 13.4 hr 7.6 hr Neutral
May 15 hr 9.2 hr Long day
June 15.9 hr 11.7 hr Long day
July 15.5 hr 10.8 hr Long day
August 14.1 hr 9.4 hr Long day
September 12.3 hr 8.9 hr Neutral
October 10.5 hr 6.8 hr Short day
November 8.9 hr 5.3 hr Short day
December 8.1 hr 4.4 hr Short day

Peak sun hours factor in typical cloud cover — use these for solar panel and shade-planning calculations.

Soil Temperature & Composting in Phillips County

Monthly soil temps tell you when to plant warm-season crops, and when your compost pile is actively working.

Why this matters: Watching soil temperature (not air) is the single biggest upgrade most new gardeners can make. Phillips County's typical curve helps you plan — but a $5 soil thermometer in the bed beats any average.

Plant Warm Crops When

Soil reaches 60°F+

Soil rarely reaches 60°F — use black plastic mulch to warm soil.

Best Month to Compost

Jul

Microbial activity peaks when soil is warm.

Active Composting

2 months

Short season — insulate pile or use indoor vermicomposting.

60°F 18° 35° 53° 70° Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
4" depth 8" depth - - - 60°F (corn, beans) - - - 70°F (tomatoes, peppers)
View detailed monthly data
MonthSoil 4" DeepSoil 8" DeepCompost ActivityTime to Finish
Jan -6°F 1°F ❄️ Dormant ~36 weeks
Feb -6°F 1°F ❄️ Dormant ~36 weeks
Mar 4°F 8°F ❄️ Dormant ~36 weeks
Apr 20°F 18°F ❄️ Dormant ~36 weeks
May 35°F 29°F ❄️ Dormant ~36 weeks
Jun 44°F 38°F 🐢 Slow ~24 weeks
Jul 51°F 46°F ♻️ Active ~14 weeks
Aug 53°F 47°F ♻️ Active ~14 weeks
Sep 43°F 43°F 🐢 Slow ~24 weeks
Oct 33°F 33°F ❄️ Dormant ~36 weeks
Nov 16°F 22°F ❄️ Dormant ~36 weeks
Dec 2°F 11°F ❄️ Dormant ~36 weeks

Highlighted rows = soil 60°F+ (safe for warm-season transplants). Compost finishes fastest during peak activity months.

Pest & Disease Pressure in Phillips County

Computed from local climate patterns — warmer, humid conditions increase pest generations and fungal disease risk.

For new gardeners: Pest pressure scales with warmth and humidity. Hot humid Phillips County sees year-round bugs and fungal disease; cold dry regions see almost none. A high pest score means crop rotation, resistant varieties, and a weekly pest-watch routine from day one.

Insect Pest Pressure

5 / 10

Moderate — common pests appear but manageable with monitoring.

Disease Risk

1.5 / 10

Low disease risk — dry conditions reduce fungal problems.

Seasonal Risk

Spring Low
Summer High
Fall Low
Winter Low
View 5 common pests in your area
PestRisk LevelPeak Months
Aphids Moderate May, Jun, Jul, Aug
Cabbage worms Low Jun, Jul, Aug
Colorado potato beetle Low Jun, Jul
Flea beetles Moderate May, Jun, Jul
Slugs Low May, Jun, Jul, Aug, Sep
Organic pest management tips
  • Maintain healthy soil with regular compost additions to build natural pest resistance
  • Practice crop rotation annually to break pest cycles
  • Encourage beneficial insects with flowering herbs like dill, fennel, and yarrow

Cover Crops for Phillips County

Cover crops protect bare soil, fix nitrogen, suppress weeds, and improve soil structure — with planting dates calibrated for your area.

For new gardeners: Cover crops fix nitrogen by hosting bacteria that pull it from the air. A vigorous legume cover crop can deliver 50-150 lbs/acre of nitrogen — meaningful for the next vegetable season.

Spring Cover Crops (2 options) — Build soil before the main growing season
Crop Plant By Terminate N-Fixing Soil Benefit
Buckwheat May 31 Jul 27 Rapid growth, attracts pollinators, suppresses weeds
White clover Apr 22 Jul 20 ✓ Yes Living mulch, fixes nitrogen, permanent ground cover
Summer Cover Crops (1 options) — Fill gaps and suppress weeds between plantings
Crop Plant By Terminate N-Fixing Soil Benefit
Sunflowers Jun 15 Aug 31 Deep roots break compaction, attract pollinators and beneficial insects
Fall Cover Crops (5 options) — Plant after harvest to protect soil over winter
Crop Plant By Terminate N-Fixing Soil Benefit
Daikon radish Jul 30 Apr 27 Deep taproot breaks compaction, excellent for clay soils
Hairy vetch Jul 15 May 4 ✓ Yes Excellent nitrogen fixer, good for depleted soils
Oats Aug 16 May 4 Quick biomass, winterkills in cold zones — no spring tillage needed
Winter rye Jun 24 May 4 Suppresses weeds, prevents erosion, breaks up compacted soil
Winter wheat Jun 21 Apr 27 Erosion control, weed suppression, good biomass

Wind & Microclimate in Phillips County

The practical takeaway: Why care about wind? Above about 10 mph, evaporation jumps and pollinators struggle to land on flowers. Phillips County's 10.1 mph average means you can plant tall crops without much support, but it doesn't mean ignore wind — a 20+ mph storm still snaps unstaked tomatoes.

Wind dries soil, stresses plants, and affects frost patterns. Understanding your exposure helps with garden placement.

Seasonal Wind Speed

Spring: 16 mph   Summer: 10 mph

Fall: 11 mph   Winter: 15 mph

Prevailing wind: W. Windy area — plant a windbreak hedge on the W side of your garden.

Windbreak Benefit

6.9/10

Moderately beneficial — a simple fence or trellis can protect delicate crops from wind stress.

Frost Pocket Risk

High

Hilly terrain with 2,347 ft of elevation range — cold air pools in low spots. Avoid planting frost-sensitive crops in valleys.

Rainwater Harvesting in Phillips County

How much water you can collect, when to collect it, and what size system you need for your garden.

The practical takeaway: Captured rainwater is better for plants than tap water (no chlorine), works during water restrictions, and reduces stormwater runoff. Phillips County's 19" annual rainfall is a meaningful pool — most homes could capture 10,000+ gallons a year with a decent system.

Annual Collection

9,419 gal

Per 1,000 sq ft of roof area (at 80% collection efficiency)

Recommended Setup

8 rain barrels (55 gal each)

For a typical 500 sq ft garden. Serious collectors: consider a 1,750 gal tank.

Legal Status

Unrestricted

Rainwater harvesting is fully legal in your state with no restrictions.

Best Collection Months

Apr, May, Aug, Oct

Highest rainfall months — your barrels will fill up quickly during these months.

Months to Draw From Storage

Feb, Nov, Dec

Dry months when you'll rely on stored water — size your storage for this gap.

Rainwater collection tips for your area
  • Your county receives approximately 18.9 inches of rain per year
  • A 1,000 sq ft roof can collect roughly 9,419 gallons annually
  • Rainwater harvesting is fully legal in your state
  • In your dry climate, every drop counts — consider a larger cistern system
  • Position collection tanks in shade to reduce evaporation and algae growth

Soil & Growing Conditions in Phillips County

Soil Type

Loam

Soil pH 6.7–7.6 · Well Drained drainage

Good candidate for raised beds to maximise drainage and extend the season.

Watering Needs

Drought stress: 5.5/10

Moderate drought pressure. Drip irrigation and mulching are highly recommended to maintain soil moisture through summer.

Season Tips

126-day frost-free season

A short season means indoor starts are critical for warm-season crops. Prioritise cold-hardy, fast-maturing varieties and use row covers to extend autumn harvests.

Your Free Printable Garden Planner

Plan every bed, every planting, every harvest — in one place. This 22-page printable includes your zone's planting calendar, a month-by-month task list, a seed inventory tracker, a harvest log, and succession-planting charts. Built to print, write in, and actually use all season.

Instant PDF download. No spam, unsubscribe any time.

Recommended for Your Garden

🧪
Soil Test Kit $12-25

Test your soil pH, nitrogen, phosphorus, and potassium levels before planting.

📏
Digital pH Meter $10-20

Get instant, accurate soil pH readings to fine-tune your amendments.

🍂
Organic Compost $8-30

Boost soil fertility and structure with rich, well-aged organic compost.

🥬 Vegetables to Grow in Phillips County

86 vegetables that grow well in Zone 3b with planting dates for Phillips County.

Show all 86 vegetables with planting dates
Plant Start Indoors Direct Sow Transplant Fall Plant Harvest Days to Maturity
Acorn Squash Apr 6 Jun 1 Jun 8 Aug 31 – Oct 5 80–100
Amaranth Mar 16 Jun 1 Jun 8 Sep 7 – Oct 12 90–120
Arugula Apr 6 May 11 May 18 Jun 29 Jun 22 – Aug 24 30–50
Asparagus Jun 1 730–1095
Beets May 11 Jun 29 Jul 6 – Aug 3 50–70
Belgian Endive Apr 6 May 11 May 18 Jun 29 Sep 7 – Sep 21 110–150
Black Beans Jun 1 Aug 31 – Oct 5 90–120
Bok Choy Apr 6 May 11 May 18 Jun 29 Jun 29 – Aug 3 40–60
Broccoli Apr 6 May 11 May 18 Jun 29 Jul 20 – Aug 31 60–90
Broccoli Rabe Apr 6 May 11 May 18 Jun 29 Jun 29 – Aug 3 40–60
Brussels Sprouts Apr 6 May 11 May 18 Jun 29 Aug 17 – Sep 21 90–130
Butternut Squash Apr 6 Jun 1 Jun 8 Sep 7 – Oct 12 85–110
Cabbage Apr 6 May 11 May 18 Jun 29 Jul 20 – Sep 14 60–100
Carrots May 11 Jun 29 Jul 13 – Aug 17 60–80
Cauliflower Apr 6 May 11 May 18 Jun 29 Jul 13 – Sep 14 55–100
Celeriac Apr 6 May 11 May 18 Jun 29 Aug 31 – Sep 21 100–120
Celery Apr 6 May 11 May 18 Jun 29 Aug 10 – Sep 21 80–120
Celtuce Apr 6 May 11 May 18 Jun 29 Jul 20 – Aug 31 60–90
Chard Apr 6 May 11 May 18 Jun 29 Jul 13 – Aug 31 50–60
Chickpeas Apr 6 May 11 May 18 Jun 29 Aug 10 – Sep 21 80–110
Chicory Apr 6 May 11 May 18 Jun 29 Jul 20 – Aug 31 60–85
Chinese Cabbage Apr 6 May 11 May 18 Jun 29 Jul 13 – Aug 10 50–70
Collard Greens Apr 6 May 11 May 18 Jun 29 Jul 13 – Sep 14 55–75
Corn Jun 1 Aug 3 – Sep 28 60–100
Cress Apr 6 May 11 May 18 Jun 29 Jun 1 – Jun 22 14–21
Crookneck Squash Apr 6 Jun 1 Jun 8 Jul 27 – Aug 24 45–60
Cucumber Apr 6 Jun 1 Jun 8 Aug 3 – Sep 28 50–70
Daikon May 11 Jun 29 Jul 6 – Aug 3 50–70
Delicata Squash Apr 6 Jun 1 Jun 8 Aug 31 – Oct 5 80–100
Edamame Jun 1 Aug 17 – Sep 28 75–100
Endive Apr 6 May 11 May 18 Jun 29 Jul 6 – Aug 10 45–65
Escarole Apr 6 May 11 May 18 Jun 29 Jul 13 – Aug 10 50–70
Fava Beans Apr 6 May 11 May 18 Jun 29 Aug 3 – Sep 14 75–100
Garlic Aug 10 Nov 9 – Dec 14 90–240
Green Beans Jun 1 Jul 27 – Sep 21 50–65
Horseradish Jun 1 Oct 5 120–180
Hubbard Squash Apr 6 Jun 1 Jun 8 Sep 21 – Oct 12 100–120
Kabocha Apr 6 Jun 1 Jun 8 Sep 7 – Oct 5 85–100
Kai Lan Apr 6 May 11 May 18 Jun 29 Jul 6 – Aug 3 45–60
Kale Apr 6 May 11 May 18 Jun 29 Jul 13 – Sep 7 50–70
Kidney Beans Jun 1 Aug 31 – Oct 5 85–110
Kohlrabi Apr 6 May 11 May 18 Jun 29 Jul 6 – Aug 10 45–65
Komatsuna Apr 6 May 11 May 18 Jun 29 Jun 22 – Jul 27 35–50
Leeks Apr 6 May 11 May 18 Jun 29 Aug 17 – Sep 21 90–150
Lentils Apr 6 May 11 May 18 Jun 29 Aug 10 – Sep 21 80–110
Lettuce Apr 6 May 11 May 18 Jun 29 Jun 22 – Aug 31 30–60
Lima Beans Jun 1 Aug 3 – Sep 14 60–90
Mache Apr 6 May 11 May 18 Jun 29 Jun 29 – Aug 3 40–60
Microgreens Apr 6 May 11 May 18 Jun 29 May 25 – Jun 22 7–21
Mizuna Apr 6 May 11 May 18 Jun 29 Jun 22 – Jul 20 30–45
Mustard Greens Apr 6 May 11 May 18 Jun 29 Jun 22 – Aug 24 30–50
Napa Cabbage Apr 6 May 11 May 18 Jun 29 Jul 13 – Aug 17 55–75
Onion Apr 6 May 11 May 18 Jun 29 Aug 17 – Sep 21 90–120
Pac Choi Apr 6 May 11 May 18 Jun 29 Jun 29 – Jul 27 40–55
Parsnip May 11 Jun 29 Aug 24 – Sep 14 100–130
Patty Pan Squash Apr 6 Jun 1 Jun 8 Jul 27 – Aug 24 45–60
Peas Apr 6 May 11 May 18 Jun 29 Jul 13 – Sep 7 55–70
Peppers Mar 2 Jun 1 Jun 8 Aug 10 – Oct 12 60–90
Pole Beans Mar 16 Jun 1 Jun 8 Aug 3 – Sep 28 55–70
Potatoes Mar 16 Jun 1 Jun 8 Aug 17 – Oct 12 70–120
Pumpkin Apr 6 Jun 1 Jun 8 Sep 7 – Oct 12 85–120
Purslane Apr 6 May 11 May 18 Jun 29 Jun 29 – Aug 3 40–60
Radish May 11 Jun 29 Jun 8 – Jun 29 22–35
Rhubarb Jun 15 365–730
Romanesco Apr 6 May 11 May 18 Jun 29 Aug 3 – Sep 14 75–100
Rutabaga May 11 Jun 29 Aug 3 – Sep 7 80–100
Salsify May 11 Jun 29 Aug 24 – Sep 14 100–130
Savoy Cabbage Apr 6 May 11 May 18 Jun 29 Jul 27 – Sep 21 70–110
Scallions Apr 6 May 11 May 18 Jun 29 Jul 13 – Aug 10 50–70
Scarlet Runner Beans Mar 16 Jun 1 Jun 8 Aug 10 – Sep 14 60–80
Shiso Mar 23 May 25 Jun 8 Aug 3 – Sep 28 50–70
Snap Peas Mar 16 Jun 1 Jun 8 Aug 3 – Sep 28 55–70
Snow Peas Apr 6 May 11 May 18 Jun 29 Jul 13 – Sep 7 50–65
Soybeans Jun 1 Aug 24 – Oct 5 80–120
Spaghetti Squash Apr 6 Jun 1 Jun 8 Sep 7 – Oct 5 85–100
Spinach Apr 6 May 11 May 18 Jun 29 Jun 22 – Aug 24 35–50
Squash (Summer) Apr 6 Jun 1 Jun 8 Jul 27 – Sep 28 45–65
Squash (Winter) Apr 6 Jun 1 Jun 8 Aug 31 – Oct 12 80–120
Sunchoke Jun 1 Sep 21 – Oct 5 110–150
Sweet Corn Jun 1 Aug 3 – Sep 14 60–90
Tatsoi Apr 6 May 11 May 18 Jun 29 Jun 22 – Jul 27 35–50
Tomatoes Mar 16 Jun 1 Jun 8 Aug 10 – Oct 12 60–85
Turnip May 11 Jun 29 Jun 22 – Jul 27 40–60
Watercress Apr 6 May 11 May 18 Jun 29 Jun 29 – Aug 3 40–60
Wax Beans Jun 1 Jul 27 – Sep 21 50–65
Zucchini Apr 6 Jun 1 Jun 8 Jul 27 – Sep 21 45–60

🍓 Fruits to Grow in Phillips County

15 fruits that grow well in Zone 3b with planting dates for Phillips County.

Show all 15 fruits with planting dates
Plant Start Indoors Direct Sow Transplant Fall Plant Harvest Days to Maturity
Alpine Strawberries Jun 15 Sep 14 – Oct 19 90–180
Aronia Jun 15 730–1095
Blueberries Jun 15 730–1095
Cranberries Jun 15 730–1095
Currants Jun 15 730–1095
Elderberries Jun 15 730–1095
Goji Berries Jun 15 730–1095
Gooseberries Jun 15 730–1095
Hardy Kiwi Jun 15 1095–1825
Haskaps Jun 15 730–1095
Jostaberry Jun 15 730–1095
Lingonberries Jun 15 730–1095
Raspberries Jun 15 365–730
Serviceberries Jun 15 730–1095
Strawberries Jun 15 Sep 14 – Oct 19 90–365

🌿 Herbs to Grow in Phillips County

20 herbs that grow well in Zone 3b with planting dates for Phillips County.

Show all 20 herbs with planting dates
Plant Start Indoors Direct Sow Transplant Fall Plant Harvest Days to Maturity
Angelica Apr 6 May 11 May 11 Jun 29 365–730
Bee Balm May 25 Aug 24 – Sep 28 90–120
Borage Apr 6 May 11 May 11 Jun 29 Jul 6 – Aug 24 50–60
Caraway Apr 6 May 11 May 11 Jun 29 365–450
Catnip May 25 Jul 27 – Sep 28 60–80
Chamomile Apr 6 May 11 May 11 Jun 29 Jul 13 – Sep 14 60–90
Chervil Apr 6 May 11 May 11 Jun 29 Jun 22 – Aug 24 40–60
Chives May 25 Jul 27 – Sep 28 60–90
Cilantro Apr 6 May 11 May 11 Jun 29 Jun 22 – Aug 24 40–60
Comfrey May 25 Jul 27 – Sep 28 60–90
Dill Apr 6 May 11 May 11 Jun 29 Jun 22 – Aug 24 40–60
Garlic Chives May 25 Jul 27 – Sep 28 60–90
Horehound May 25 Aug 10 – Sep 28 75–90
Hyssop May 25 Aug 3 – Sep 28 70–90
Lemon Balm May 25 Jul 27 – Sep 14 60–70
Lovage May 25 Aug 3 – Sep 28 70–90
Mint May 25 Jul 27 – Sep 28 60–90
Parsley Apr 6 May 11 May 11 Jun 29 Jul 13 – Sep 14 60–80
Sorrel Apr 6 May 11 May 11 Jun 29 Jun 22 – Aug 24 40–60
Valerian May 25 Sep 28 120–180

🌸 Flowers to Grow in Phillips County

49 flowers that grow well in Zone 3b with planting dates for Phillips County.

Show all 49 flowers with planting dates
Plant Start Indoors Direct Sow Transplant Fall Plant Bloom Days to Maturity
Ageratum Mar 23 Jun 1 Jun 1 Jul 27 – Sep 28 60–75
Alliums Aug 10 Sep 21 – Oct 19 28–42
Astilbe Mar 9 Jun 1 Aug 24 – Oct 12 70–100
Bachelor's Button Mar 23 May 11 May 18 Jul 20 – Sep 14 60–90
Begonias Mar 2 Jun 1 Aug 10 – Oct 5 70–90
Black-eyed Susan Mar 9 May 18 Jun 1 Aug 24 – Oct 26 60–80
Bleeding Hearts Mar 9 Jun 1 Jul 27 – Sep 7 60–90
Calendula Mar 30 May 11 May 18 Jul 6 – Sep 14 50–70
Celosia Apr 6 Jun 8 Jun 8 Aug 10 – Oct 19 60–90
Columbine Mar 9 Jun 1 Jun 1 Jul 27 – Sep 7 70–100
Coreopsis Mar 9 May 25 Jun 1 Aug 24 – Oct 26 60–80
Cosmos Apr 20 May 25 May 25 Aug 3 – Oct 12 60–90
Crocus Aug 10 Jun 8 – Jul 6 10–20
Daffodils Aug 10 Jun 15 – Jul 13 20–40
Dahlias Apr 20 Jun 1 Jun 1 Sep 7 – Oct 26 70–120
Daylily Mar 9 Jun 1 Sep 7 – Oct 26 60–90
Dianthus Mar 9 May 4 May 18 Jul 6 – Aug 31 60–80
Echinacea (Purple Coneflower) Mar 9 Jun 1 Jun 1 Aug 31 – Oct 26 70–90
Foxglove Mar 9 Jun 1 Jun 1 Jul 27 – Sep 7 80–120
Gaillardia (Blanket Flower) Mar 23 Jun 1 Jun 1 Aug 10 – Nov 2 70–100
Geraniums Mar 2 Jun 1 Aug 10 – Oct 5 70–100
Gladiolus Jun 1 Jun 1 Sep 7 – Oct 26 70–100
Hostas Feb 23 Jun 1 Sep 7 – Oct 26 60–90
Hyacinths Aug 10 Jul 6 – Jul 27 14–28
Hydrangeas Feb 23 Jun 1 Aug 24 – Oct 12 90–150
Impatiens Mar 16 Jun 1 Aug 17 – Oct 5 60–75
Irises Division Jun 1 Jul 27 – Aug 24 60–100
Larkspur Apr 13 Jun 22 – Aug 3 60–90
Lilies Division Jun 1 Aug 24 – Oct 19 70–120
Lobelia Mar 9 May 25 Jul 20 – Sep 7 70–80
Lupine Mar 9 Jun 1 Jun 1 Jul 27 – Sep 7 75–100
Marigolds Apr 6 Jun 1 Jun 1 Jul 27 – Oct 5 50–70
Nasturtium Apr 20 Jun 1 Jun 1 Jul 27 – Oct 5 55–65
Pansy Feb 23 May 18 Jul 13 – Aug 24 70–90
Peonies Division Jun 1 Aug 10 – Sep 7 90–120
Petunia Mar 16 Jun 1 Aug 17 – Oct 12 70–90
Phlox Mar 9 Jun 1 Jun 1 Aug 24 – Oct 19 80–110
Portulaca Apr 6 Jun 8 Jun 8 Jul 27 – Sep 28 50–70
Roses Feb 23 Jun 1 Aug 24 – Oct 26 90–180
Salvia Mar 9 Jun 1 Aug 10 – Oct 5 70–90
Sedum (Stonecrop) Mar 9 Jun 1 Oct 5 – Nov 16 60–90
Snapdragon Mar 2 May 18 Jul 27 – Sep 14 70–100
Sunflower Apr 27 Jun 1 Jun 1 Aug 24 – Oct 19 70–100
Sweet Alyssum Mar 23 May 18 May 18 Jun 29 – Aug 24 45–60
Sweet Pea Mar 30 Apr 20 May 18 Aug 10 – Sep 21 65–85
Tulips Aug 10 Jun 29 – Jul 20 15–30
Vinca (Annual) Mar 2 Jun 1 Aug 10 – Oct 5 70–90
Yarrow Mar 9 May 18 Jun 1 Aug 24 – Oct 26 60–90
Zinnia Apr 20 Jun 1 Jun 1 Aug 10 – Oct 12 60–70

Monthly Planting Guide for Phillips County

Gardening Guides & Resources

Helpful guides from The Ultimate Homestead to improve your garden in Phillips County.

Frequently Asked Questions

What planting zone is Phillips County, MT?

Phillips County is in USDA Hardiness Zone 3b. This zone classification determines which perennial plants survive winter and sets the baseline for frost timing across the county.

When is the last frost in Phillips County, MT?

Based on 31 years of NOAA weather station data, the median last spring frost in Phillips County falls around May 18. In 8 out of 10 years, last frost lands between May 1 and May 31 — a 30-day window of variability. Use May 31 as your conservative safe-to-plant date for frost-sensitive crops.

When is the first fall frost in Phillips County, MT?

The median first fall frost in Phillips County arrives around September 21. In cold years it can arrive as early as September 8; in mild years as late as October 5. Harvest or protect frost-sensitive crops — tomatoes, peppers, basil, squash — before this date.

How long is the growing season in Phillips County?

Phillips County has a frost-free growing season of approximately 126 days. Focus on short-season varieties and start warm-season crops indoors 6–8 weeks before last frost. Climate records show the growing season is trending longer by about 2.47 days per decade.

What is the soil like in Phillips County for gardening?

Phillips County has predominantly Loam soil with a pH range of 6.7–7.6 and Well Drained drainage. Most vegetables and herbs grow well with standard composting and seasonal soil amendment.

What is grown commercially in Phillips County?

Phillips County has commercial agriculture that includes Hay, Cattle, Wheat, Barley, Sugar Beets. These crops reflect the local climate and soil conditions — what succeeds commercially often translates well to home gardens in the same area.

Is Phillips County a good location for home gardening?

Phillips County scores 32/100 (Challenging) on our Microclimate Index, which combines frost reliability, drought pressure, soil challenge, elevation risk, and long-term climate trend. Gardening here benefits from close attention to frost timing and season extension due to the challenging microclimate factors.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA GHCN-D daily station data (1994–2024) from 3 weather stations in or near Phillips County (31 years of records). Frost dates represent 50% probability averages; local conditions vary by elevation and microclimate. 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.