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When to Plant Tomatoes in McCone County, MT

McCone County, Montana Zone 4a May

May in the garden — McCone County, Montana

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

Avg. last frost May 14
Avg. first frost September 22
Soil temp (4") 39°F
Watering High
Pest pressure Low
Daylight 14.9 hrs
  1. Scatter tomatoes into prepared beds

    These tolerate cool soil, so you're not gambling by sowing now.

June prep starts now
  • Transplants going out: tomatoes

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Tomatoes are the most popular home garden crop, available in thousands of varieties from tiny cherries to massive beefsteaks. They are warm-season plants needing full sun.

McCone County, Montana is in USDA Zone 4a. The average last spring frost is May 14 and the first fall frost is September 22, giving you a growing season of approximately 131 days.

At an elevation of 5,568 feet, McCone County receives approximately 22 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Tomatoes to ensure they mature before fall.

McCone County, MT (Zone 4a) Short season
131 days
Last Spring Frost May 14
131 growing days
First Fall Frost September 22

McCone County Soil Profile

Soil Type

Loam

Soil pH

6.7-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 8 Transplant: May 31 🍅 Harvest: Aug 2 – Oct 11
Recommended (50%) ✗ May not fit
Start indoors: Mar 12 Transplant: Jun 4 🍅 Harvest: Aug 6 – Oct 15
Safe Start (90%) ✗ May not fit
Start indoors: Mar 27 Transplant: Jun 19 🍅 Harvest: Aug 21 – Oct 30

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 McCone County

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

Soil pH

Your soil pH (6.7–8.2) is more alkaline than Tomatoes prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

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

How to Plant Tomatoes

0.5"
Planting Depth
24"
Between Plants
36"
Between Rows

Succession Planting Tomatoes

2
successive plantings in your 131-day season

Sow every 6.9 weeks. Last sowing by Jun 29 to harvest before frost.

Plant Water Budget

Plant needs
1.2″/week
Rainfall provides
0.7″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 692 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Tomatoes

Tomatoes needs approximately 1.2 inches of water per week (5.2" per month). Here's how your county's rainfall compares month by month.

Month Tomatoes Needs Rainfall You Supplement Action
Jan 1.7" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 2.6" 0" ❄️ Dormant
May 5.2" 2.7" 2.5" 💧 Light watering
Jun 5.2" 1.4" 3.8" 🚿 Regular watering
Jul 5.2" 1.9" 3.3" 🚿 Regular watering
Aug 5.2" 2.3" 2.9" 🚿 Regular watering
Sep 5.2" 1.8" 3.4" 🚿 Regular watering
Oct 1.7" 0" ❄️ Dormant
Nov 1.5" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

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

Tomatoes 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.

Tomatoes needs ~834 GDD — county provides 1,506 GDD Excellent fit

Tomatoes Planting Timeline — McCone County, MT

Tomatoes Planting Calendar

Activity When Date Range
Start Indoors March 12 Mar 12 – Mar 26
Transplant Outdoors June 4 Jun 4 – Jun 18
Direct Sow May 28 May 28 – Jun 18
Harvest August 6 Aug 6 – Oct 15

Plant 0.5" deep · 24" apart · Rows 36" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.2"/week · 1-2 times/week

📅 Days to Maturity

60–85 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 4a

📆 Growing Season

131 days in McCone County

Growing Tips for Tomatoes in McCone County

Direct sow Tomatoes outdoors after May 14 in McCone County when soil has warmed and frost danger has passed.

Common pests for Tomatoes in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.

McCone County receives only 22" of rain annually. Tomatoes needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Start seeds indoors 6-8 weeks before last frost. Bury transplants deep to encourage rooting along the stem. Provide consistent moisture to prevent blossom end rot and cracking.

Recommended Tomatoes Varieties for McCone County

Choose determinate, early-maturing varieties for your short season

Early Girl (52d) Stupice (55d) Glacier (55d) Sub Arctic Plenty (45d)

Companion Planting

Good Companions

Avoid Planting Near

  • Cabbage
  • Fennel
  • Potatoes

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Tomatoes Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Scoop seeds from ripe fruit; ferment 2-3 days to remove gel coating.
Storage Store airtight; viable 4-6 years at 35°F, under 45% humidity.

Isolate 25 ft between varieties for purity. Use open-pollinated varieties for true-to-type seeds.

Frequently Asked Questions

When should I plant Tomatoes in McCone County, MT?

McCone County is in Zone 4a with an average last frost of May 14. Plan your Tomatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is McCone County, MT?

McCone County, Montana is in USDA Hardiness Zone 4a. The average last spring frost is May 14 and first fall frost is September 22.

🌱

Your McCone County Garden Planner — Free

A 24-page printable planner built for McCone County (Zone 4a). 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 McCone 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.