When to Plant in Montana: A Month-by-Month Guide for Vegetables, Flowers, and Trees
Montana’s climate is beautiful but challenging for gardeners. With short growing seasons,
unpredictable spring frosts, and early fall freezes, knowing when to plant in Montana
is critical for success. This guide breaks down planting timelines by frost dates, crop type,
and month so you can plan confidently no matter where you live in the state.
Quick Answer: When Do Most People Plant in Montana?
- Cool-season crops (lettuce, peas, spinach): April to early May
- Warm-season crops (tomatoes, peppers, squash): Late May to mid-June
- Fall planting (garlic, perennials, trees): September to October
The exact timing depends heavily on elevation, valley location, and your local frost dates.
Montana gardeners must always plan around frost first, then soil temperature.
Understanding Montana Frost Dates
Frost dates determine nearly everything about planting in Montana. The state spans multiple
climate zones, so averages vary widely.
| Region | Average Last Spring Frost | Average First Fall Frost |
|---|---|---|
| Western Montana (valleys) | May 5 – May 20 | September 20 – October 5 |
| Central Montana | May 15 – June 1 | September 10 – September 25 |
| Eastern Montana | May 10 – May 30 | September 15 – October 1 |
| High elevation areas | Late May – Mid June | Early September |
Always assume frost can happen outside these averages. Many Montana gardeners wait until
after Mother’s Day to plant frost-sensitive crops.
What to Plant in Montana by Month
March to Early April: Indoor Prep and Cold-Hardy Starts
While the ground is usually still frozen, this is the time to start seeds indoors.
- Tomatoes
- Peppers
- Broccoli
- Cauliflower
- Herbs like basil and thyme
Late April to Early May: Cool-Season Crops
Once the soil is workable, Montana gardeners can plant cold-tolerant crops outdoors.
- Peas
- Spinach
- Lettuce
- Radishes
- Onions and shallots
- Potatoes
Late May to Mid-June: Warm-Season Planting
This is the most important planting window in Montana. Wait until nighttime temperatures
consistently stay above 45°F.
- Tomatoes (transplants)
- Peppers
- Beans
- Corn
- Squash and zucchini
- Cucumbers
- Pumpkins
July: Succession Planting
July is ideal for planting fast-growing crops that will mature before fall frost.
- Bush beans
- Carrots
- Beets
- More lettuce
August to September: Fall Crops and Garlic
As summer cools, Montana gardeners can plant crops that thrive in cooler temperatures.
- Spinach
- Kale
- Arugula
- Garlic (best planted in October)
When to Plant Trees and Shrubs in Montana
Trees and shrubs do best when planted during cooler periods with consistent moisture.
- Spring: Late April through June
- Fall: September until the ground freezes
Fall planting is often preferred because roots establish while the plant is dormant,
leading to stronger growth the following spring.
Tips for Successful Planting in Montana
- Use frost blankets or row covers for surprise cold snaps
- Choose short-season and cold-hardy varieties
- Warm soil with black plastic or raised beds
- Harden off seedlings slowly before transplanting
Frequently Asked Questions
Is Montana too cold to garden?
Not at all. Montana simply requires planning. With the right timing and plant varieties,
gardeners can have productive gardens every year.
Can I plant tomatoes before Memorial Day?
Only with protection. Most Montana gardeners wait until late May or early June to avoid
frost damage.
What is the safest planting date in Montana?
After the last average frost for your region—often around late May—is the safest time
for frost-sensitive plants.
Final Thoughts
Knowing when to plant in Montana is about working with nature, not against it.
By respecting frost dates, soil temperature, and Montana’s short growing season,
you can grow thriving vegetables, flowers, and landscapes year after year.
