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When to Plant Cress in Glacier County, MT

Glacier County, Montana Zone 4b May

What to do in May

We've pulled the most time-sensitive tasks for Glacier County, Montana this May and put them front and centre. Tackle them in order.

Avg. last frost May 22
Avg. first frost September 18
Soil temp (4") 30°F
Watering High
Pest pressure Low
Daylight 15 hrs
  1. Transplant cress outside

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

  2. Direct-sow cress

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

A few tasks this May that'll pay off in June
  • First harvests: cress
  • Fall sowing: cress

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Garden cress is one of the fastest-growing edibles, producing peppery sprouts in as little as two weeks. It is excellent for microgreens and garnishes.

Glacier County, Montana is in USDA Zone 4b. The average last spring frost is May 22 and the first fall frost is September 18, giving you a growing season of approximately 119 days.

At an elevation of 8,147 feet, Glacier County receives approximately 13.3 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Cress to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Cress successfully. Mulch heavily to conserve soil moisture.

Glacier County, MT (Zone 4b) Short season
119 days
Last Spring Frost May 22
119 growing days
First Fall Frost September 18

Glacier County Soil Profile

Soil Type

Loam

Soil pH

6.3-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (84 days to spare)
Start indoors: Apr 3 Transplant: May 15 🍅 Harvest: May 29 – Jun 19
Recommended (50%) ✓ Fits season (84 days to spare)
Start indoors: Apr 10 Transplant: May 22 🍅 Harvest: Jun 5 – Jun 26
Safe Start (90%) ✓ Fits season (71 days to spare)
Start indoors: Apr 30 Transplant: Jun 11 🍅 Harvest: Jun 25 – Jul 16

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 Glacier County

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

Soil pH

Your soil pH (6.3–8.1) is more alkaline than Cress prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

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

How to Plant Cress

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 Cress

10
successive plantings in your 119-day season

Sow every 1.6 weeks. Last sowing by Aug 28 to harvest before frost.

For a dedicated fall crop, sow by Jun 26.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 674 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Cress

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

Month Cress Needs Rainfall You Supplement Action
Jan 0.8" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1" 0" ❄️ Dormant
Apr 1.3" 0" ❄️ Dormant
May 4.3" 1.6" 2.7" 🚿 Regular watering
Jun 4.3" 1" 3.3" 🚿 Regular watering
Jul 4.3" 1.3" 3" 🚿 Regular watering
Aug 4.3" 1.4" 2.9" 🚿 Regular watering
Sep 4.3" 1.1" 3.2" 🚿 Regular watering
Oct 1.3" 0" ❄️ Dormant
Nov 1" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

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

Cress 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.

Cress needs ~175 GDD — county provides 1,190 GDD Excellent fit

Cress Planting Timeline — Glacier County, MT

Cress Planting Calendar

Activity When Date Range
Start Indoors April 10 Apr 10 – Apr 24
Transplant Outdoors May 22 May 22 – Jun 5
Direct Sow May 15 May 15 – Jun 5
Harvest June 5 Jun 5 – Jun 26
Fall Sowing June 26 Jun 26 – Jul 10

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
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

14–21 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 4b

📆 Growing Season

119 days in Glacier County

Growing Tips for Cress in Glacier County

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

Your generous 119.0-day season in Glacier County allows multiple plantings of Cress. Sow every 7.0 days for continuous harvest.

Common pests for Cress in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

Glacier County receives only 13" of rain annually. Cress needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Sow seeds thickly on moist soil or paper towels. Keep moist and harvest when 2-3 inches tall. Succession sow every few days for continuous supply. Grows well indoors year-round.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Cress in Glacier County, MT?

Glacier County is in Zone 4b with an average last frost of May 22. Plan your Cress planting based on this frost date — see the calendar above for exact timing.

What planting zone is Glacier County, MT?

Glacier County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 22 and first fall frost is September 18.

🌱

Your Glacier County Garden Planner — Free

A 24-page printable planner built for Glacier 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 Glacier 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.