Use this planting calendar to find the best times of the year to grow fruits, vegetables, herbs, flowers, and other popular plants in Roundup, MT, based on the USDA Hardiness Zone 4b.
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Roundup, MT Frost Dates & Growing Season
Last Spring Frost Date for Roundup, MT
The average last frost date in spring for Roundup is May 20th. For gardeners planting sensitive crops like tomatoes, peppers, and basil, it is generally recommended to wait until June 3rd before moving plants outdoors. Waiting these extra few weeks significantly reduces the risk of a late freeze damaging young transplants.
First Fall Frost Date for Roundup, MT
The average first frost date in fall for Roundup is September 25th. This date marks the approximate end of the growing season for tender plants. Gardeners should plan to harvest frost-sensitive vegetables or provide heavy protection (such as row covers) before this date to avoid crop loss.
Growing Season Length in Roundup, MT
Based on historical frost data, the estimated growing season length in Roundup is approximately 128 days. This duration determines which vegetable varieties have enough time to reach maturity before the winter cold sets in. Short-season varieties are recommended for crops that require a longer warm period.
Please note: These dates are climatological averages. Actual weather conditions vary by year. Always check the local 10-day forecast before planting.
Roundup, MT Planting Calendar
This weekly planting calendar displays the ideal windows for starting seeds, transplanting, and harvesting your plants.
Roundup, MT Monthly Planting Recommendations
March
In March, recommended activities include starting French Lavender seeds indoors (from March 11th to March 25th), starting Onion seeds indoors (from March 11th to March 25th), and starting Snapdragon seeds indoors (from March 11th to March 25th).
April
In April, recommended activities include direct sowing Potato (from April 22nd to May 6th), starting Marigold seeds indoors (from April 8th to April 22nd), and direct sowing Chervil (from April 22nd to May 6th).
May
In May, recommended activities include direct sowing Hyssop (from May 6th to May 20th), direct sowing Nasturtium (from May 27th to June 3rd), and direct sowing Cucumber (from May 27th to June 10th).
June
In June, recommended activities include direct sowing Butterfly Pea (from June 3rd to June 17th), direct sowing Black Bean (from June 3rd to June 17th), and direct sowing Chia (from June 3rd to June 17th).