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When to Plant Chard in Mineral County, MT

Mineral County, Montana Zone 6a May

Top priorities for Mineral County, Montana gardeners in May

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Mineral County, Montana.

Avg. last frost May 30
Avg. first frost September 20
Soil temp (4") 44°F
Watering High
Pest pressure Low
Daylight 14.9 hrs
  1. Transplant chard outside

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

  2. Direct-sow chard

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

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Swiss chard is a colorful, heat-tolerant green with large crinkled leaves and vibrant stalks in red, yellow, and white. Both the leaves and stems are edible and nutritious.

Mineral County, Montana is in USDA Zone 6a. The average last spring frost is May 30 and the first fall frost is September 20, giving you a growing season of approximately 113 days.

At an elevation of 5,389 feet, Mineral County receives approximately 12.5 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Chard to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Chard successfully. Mulch heavily to conserve soil moisture.

Mineral County, MT (Zone 6a) Short season
113 days
Last Spring Frost May 30
113 growing days
First Fall Frost September 20

Mineral County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (13 days to spare)
Start indoors: Apr 9 Transplant: May 14 🍅 Harvest: Jul 9 – Aug 27
Recommended (50%) ✓ Fits season (8 days to spare)
Start indoors: Apr 25 Transplant: May 30 🍅 Harvest: Jul 25 – Sep 12
Safe Start (90%) ✓ Fits season (8 days to spare)
Start indoors: May 15 Transplant: Jun 19 🍅 Harvest: Aug 14 – Oct 2

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 Mineral County

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

Soil pH

Your soil pH (6.7–7.7) is more alkaline than Chard prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Chard.

Organic Matter

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

How to Plant Chard

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Chard

2
successive plantings in your 113-day season

Sow every 5.7 weeks. Last sowing by Jul 22 to harvest before frost.

For a dedicated fall crop, sow by Jul 12.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.5″/week
You supply
0.7″/week
Watering frequency 1-2 times/week
Season total 694 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Chard

Chard needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.

Month Chard Needs Rainfall You Supplement Action
Jan 0.9" 0" ❄️ Dormant
Feb 0.7" 0" ❄️ Dormant
Mar 1" 0" ❄️ Dormant
Apr 1.1" 0" ❄️ Dormant
May 3.5" 1.6" 1.9" 🚿 Regular watering
Jun 3.5" 0.9" 2.6" 🚿 Regular watering
Jul 3.5" 1.2" 2.3" 🚿 Regular watering
Aug 3.5" 1.3" 2.2" 🚿 Regular watering
Sep 3.5" 1.1" 2.4" 🚿 Regular watering
Oct 1.2" 0" ❄️ Dormant
Nov 0.9" 0" ❄️ Dormant
Dec 0.6" 0" ❄️ Dormant

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

Chard 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.

Chard needs ~715 GDD — county provides 1,469 GDD Excellent fit

Chard Planting Timeline — Mineral County, MT

Chard Planting Calendar

Activity When Date Range
Start Indoors April 25 Apr 25 – May 9
Transplant Outdoors May 30 May 30 – Jun 13
Direct Sow May 16 May 16 – Jun 6
Harvest July 25 Jul 25 – Sep 12
Fall Sowing July 12 Jul 12 – Jul 26

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.8"/week · 1-2 times/week

📅 Days to Maturity

50–60 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6a

📆 Growing Season

113 days in Mineral County

Growing Tips for Chard in Mineral County

Direct sow Chard outdoors after May 30 in Mineral County when soil has warmed and frost danger has passed.

General growing tips

Direct sow or transplant after last frost. Harvest outer leaves regularly to encourage continuous production. Chard tolerates both heat and light frost.

Companion Planting

Good Companions

Avoid Planting Near

  • Corn
  • Cucumbers

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Chard in Mineral County, MT?

Mineral County is in Zone 6a with an average last frost of May 30. Plan your Chard planting based on this frost date — see the calendar above for exact timing.

What planting zone is Mineral County, MT?

Mineral County, Montana is in USDA Hardiness Zone 6a. The average last spring frost is May 30 and first fall frost is September 20.

🌱

Your Mineral County Garden Planner — Free

A 24-page printable planner built for Mineral County (Zone 6a). 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 Mineral 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.