Use this planting calendar to find the best times of the year to grow fruits, vegetables, herbs, flowers, and other popular plants in Irwin, IA, based on the USDA Hardiness Zone 5b.
On this page:
Irwin, IA Frost Dates & Growing Season
Last Spring Frost Date for Irwin, IA
The average last frost date in spring for Irwin is May 1st. For gardeners planting sensitive crops like tomatoes, peppers, and basil, it is generally recommended to wait until May 15th 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 Irwin, IA
The average first frost date in fall for Irwin is October 6th. 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 Irwin, IA
Based on historical frost data, the estimated growing season length in Irwin is approximately 158 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.
Irwin, IA Planting Calendar
This weekly planting calendar displays the ideal windows for starting seeds, transplanting, and harvesting your plants.
Irwin, IA Monthly Planting Recommendations
February
In February, recommended activities include starting Leek seeds indoors (from February 20th to March 6th), starting Celery seeds indoors (from February 20th to March 6th), and starting Begonia seeds indoors (from February 20th to March 6th).
March
In March, recommended activities include starting Kale seeds indoors (from March 20th to April 3rd), starting Moonflower seeds indoors (from March 20th to April 3rd), and starting Coneflower seeds indoors (from March 6th to March 20th).
April
In April, recommended activities include starting Cantaloupe seeds indoors (from April 3rd to April 17th), direct sowing Lentil (from April 17th to May 1st), and direct sowing Mustard (from April 3rd to April 17th).
May
In May, recommended activities include direct sowing Anise (from May 8th to May 15th), direct sowing Zucchini (from May 8th to May 22nd), and direct sowing Mung Bean (from May 15th to May 29th).