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When to plant Microgreens in Fallon County, MT

In Zone 4b (Fallon County), direct-sow Microgreens between May 13 and June 3 for spring, after the May 20 last-frost mark. A second sowing from June 28 to July 12 extends the harvest into fall.

When to Plant Microgreens in Fallon County, MT

Fallon County, Montana Zone 4b July

July in the garden — Fallon County, Montana

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

Avg. last frost May 20
Avg. first frost September 20
Soil temp (4") 51°F
Watering High
Pest pressure High
Daylight 15.3 hrs
  1. Fire up the seed-starting tray: microgreens

    These need a head start before your last frost (May 20). Sow into cells now so you're ready to transplant in a few weeks.

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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.

Fallon County, Montana is in USDA Zone 4b. The average last spring frost is May 20 and the first fall frost is September 20, giving you a growing season of approximately 123 days.

At an elevation of 6,441 feet, Fallon County receives approximately 19.8 inches of rainfall annually with predominantly loam soil. Summer highs average 81°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.

Fallon County, MT (Zone 4b) Short season
123 days
Last Spring Frost May 20
123 growing days
First Fall Frost September 20

Fallon County Soil Profile

Soil Type

Loam

Soil pH

6.2-8.3

Drainage

Well Drained

Microgreens Planting Risk Windows

Early Start (70% safe) ✓ Fits season (87 days to spare)
Start indoors: Apr 2 Transplant: May 14 🍅 Harvest: May 21 – Jun 18
Recommended (50%) ✓ Fits season (88 days to spare)
Start indoors: Apr 8 Transplant: May 20 🍅 Harvest: May 27 – Jun 24
Safe Start (90%) ✓ Fits season (83 days to spare)
Start indoors: Apr 27 Transplant: Jun 8 🍅 Harvest: Jun 15 – Jul 13

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 Fallon County

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

Soil pH

Your soil pH (6.2–8.3) is more alkaline than Microgreens prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.2%). 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 123-day season

Sow every 0.7 weeks. Last sowing by Aug 30 to harvest before frost.

For a dedicated fall crop, sow by Jun 28.

Microgreens Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 425 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 1.3" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 1.8" 0" ❄️ Dormant
Apr 2.1" 0" ❄️ Dormant
May 4.3" 2.7" 1.6" 💧 Light watering
Jun 4.3" 1.4" 2.9" 🚿 Regular watering
Jul 4.3" 1.6" 2.7" 🚿 Regular watering
Aug 4.3" 1.9" 2.4" 🚿 Regular watering
Sep 4.3" 1.6" 2.7" 🚿 Regular watering
Oct 1.7" 0" ❄️ Dormant
Nov 1.2" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Fallon 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 ~150 GDD — county provides 1,322 GDD Excellent fit

Microgreens Planting Timeline — Fallon County, MT

Microgreens Planting Calendar

Activity When Date Range
Start Indoors April 8 Apr 8 – Apr 22
Transplant Outdoors May 20 May 20 – Jun 3
Direct Sow May 13 May 13 – Jun 3
Harvest May 27 May 27 – Jun 24
Fall Sowing June 28 Jun 28 – Jul 12

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

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 4b

📆 Growing Season

123 days in Fallon County

Growing Tips for Microgreens in Fallon County

Direct sow Microgreens outdoors after May 20 in Fallon County when soil has warmed and frost danger has passed.

Your generous 123.0-day season in Fallon County allows multiple plantings of Microgreens. Sow every 3.0 days for continuous harvest.

Fallon County receives only 20" 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 Fallon County, MT?

Fallon County is in Zone 4b with an average last frost of May 20. Plan your Microgreens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Fallon County, MT?

Fallon County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 20 and first fall frost is September 20.

When should I plant Microgreens in Fallon County, MT?

In Fallon County, MT, plant Microgreens after the last frost (around May 20) and before the first frost (around September 20). Best results when soil holds above 50°F.

What growing zone is Fallon County, MT for Microgreens?

Fallon County sits in USDA Zone 4b. Microgreens grows reliably in zones 1a through 13b, so it's a good fit here.

Can Microgreens grow in Fallon County's climate?

Yes — Microgreens grows well in Fallon County's temperate climate. Fallon County averages a 123-day frost-free season, with last frost around May 20 and first frost around September 20.

🌱

Your Fallon County Garden Planner — Free

A 22-page printable planner built for Fallon County (Zone 4b). 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 Fallon County, MT. Local conditions may vary. Last updated: July 2026.

Sources & credits

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