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When to Plant Microgreens in Phillips County, MT

Phillips County, Montana Zone 3b May

Your May game plan for Phillips County, Montana

Your Phillips County, Montana garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost May 18
Avg. first frost September 21
Soil temp (4") 35°F
Watering High
Pest pressure Low
Daylight 15 hrs
  1. Move microgreens into the garden

    Your last frost (May 18) has passed. These warm-season crops can handle outdoor soil now.

  2. Direct-sow microgreens

    Rake a smooth bed, make a shallow furrow, drop seeds at the spacing on the packet, water gently, walk away.

  3. Pick microgreens

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

Coming up in June — start thinking about
  • Starting indoors: microgreens
  • First harvests: microgreens
  • Fall sowing: microgreens

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Microgreens are young seedlings of vegetables and herbs harvested at the cotyledon or first true leaf stage. They pack concentrated flavors and nutrients in a tiny package.

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

Phillips County, MT (Zone 3b) Short season
126 days
Last Spring Frost May 18
126 growing days
First Fall Frost September 21
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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 (89 days to spare)
Start indoors: Mar 31 Transplant: May 12 🍅 Harvest: May 19 – Jun 16
Recommended (50%) ✓ Fits season (91 days to spare)
Start indoors: Apr 6 Transplant: May 18 🍅 Harvest: May 25 – Jun 22
Safe Start (90%) ✓ Fits season (92 days to spare)
Start indoors: Apr 19 Transplant: May 31 🍅 Harvest: Jun 7 – Jul 5

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 Microgreens's growing requirements.

Soil pH

Your soil pH (6.7–7.6) is more alkaline than Microgreens prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Phillips County is excellent for Microgreens — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

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

How to Plant Microgreens

0.5"
Planting Depth
2"
Between Plants
6"
Between Rows

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Succession Planting Microgreens

24
successive plantings in your 126-day season

Sow every 0.7 weeks. Last sowing by Aug 31 to harvest before frost.

For a dedicated fall crop, sow by Jun 29.

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 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Microgreens

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

Month Microgreens Needs Rainfall You Supplement Action
Jan 1.4" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.6" 0" ❄️ Dormant
Apr 1.9" 0" ❄️ Dormant
May 4.3" 2.4" 1.9" 💧 Light watering
Jun 4.3" 1.4" 2.9" 🚿 Regular watering
Jul 4.3" 1.6" 2.7" 🚿 Regular watering
Aug 4.3" 2" 2.3" 🚿 Regular watering
Sep 4.3" 1.4" 2.9" 🚿 Regular watering
Oct 1.8" 0" ❄️ Dormant
Nov 1.3" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

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

Microgreens 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.

Microgreens needs ~140 GDD — county provides 1,260 GDD Excellent fit

Microgreens Planting Timeline — Phillips County, MT

Microgreens Planting Calendar

Activity When Date Range
Start Indoors April 6 Apr 6 – Apr 20
Transplant Outdoors May 18 May 18 – Jun 1
Direct Sow May 11 May 11 – Jun 1
Harvest May 25 May 25 – Jun 22
Fall Sowing June 29 Jun 29 – Jul 13

Plant 0.5" deep · 2" apart · Rows 6" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Transplant Outdoors Direct Sow Harvest
June Transplant Outdoors Direct Sow Fall Sowing Harvest
July Fall Sowing
August
September
October
November
December
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Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

7–21 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 3b

📆 Growing Season

126 days in Phillips County

Growing Tips for Microgreens in Phillips County

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

Your generous 126.0-day season in Phillips County allows multiple plantings of Microgreens. Sow every 3.0 days for continuous harvest.

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

General growing tips

Sow seeds densely on shallow trays of moist growing medium. Cover until germination, then provide light. Harvest with scissors when 1-3 inches tall. Grow year-round indoors.

Frequently Asked Questions

When should I plant Microgreens in Phillips County, MT?

Phillips County is in Zone 3b with an average last frost of May 18. Plan your Microgreens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Phillips County, MT?

Phillips County, Montana is in USDA Hardiness Zone 3b. The average last spring frost is May 18 and first fall frost is September 21.

🌱

Your Phillips County Garden Planner — Free

A 24-page printable planner built for Phillips County (Zone 3b). 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 Phillips County, MT. 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.