Use this planting calendar to find the best times of the year to grow fruits, vegetables, herbs, flowers, and other popular plants in Sullivan, WI, based on the USDA Hardiness Zone 5b.
On this page:
Sullivan, WI Frost Dates & Growing Season
Last Spring Frost Date for Sullivan, WI
The average last frost date in spring for Sullivan is May 7th. For gardeners planting sensitive crops like tomatoes, peppers, and basil, it is generally recommended to wait until May 21st 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 Sullivan, WI
The average first frost date in fall for Sullivan is October 8th. 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 Sullivan, WI
Based on historical frost data, the estimated growing season length in Sullivan is approximately 154 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.
Sullivan, WI Planting Calendar
This weekly planting calendar displays the ideal windows for starting seeds, transplanting, and harvesting your plants.
Sullivan, WI Monthly Planting Recommendations
February
In February, recommended activities include starting Lavender seeds indoors (from February 26th to March 12th), starting Snapdragon seeds indoors (from February 26th to March 12th), and starting Pansy seeds indoors (from February 26th to March 12th).
March
In March, recommended activities include starting Moonflower seeds indoors (from March 26th to April 9th), starting Broccoli seeds indoors (from March 12th to March 26th), and starting Ground Cherry seeds indoors (from March 12th to March 26th).
April
In April, recommended activities include direct sowing Carrot (from April 16th to April 30th), direct sowing Chives (from April 9th to April 23rd), and starting Cantaloupe seeds indoors (from April 9th to April 23rd).
May
In May, recommended activities include direct sowing Lemon Balm (from May 7th to May 21st), direct sowing Cantaloupe (from May 14th to May 28th), and direct sowing Runner Bean (from May 14th to May 28th).