Missouri Frost Dates & Growing Season Guide
Missouri (MO) spans USDA hardiness zones 6a, 6b, with growing seasons ranging from 193 days in Springfield to 209 days in St. Louis. The average growing season across the state is approximately 200 days.
Missouri City Frost Dates
The table below shows the average last spring frost date, first fall frost date, growing season length, and USDA hardiness zone for each city. Click a city name for detailed planting calendars and zone information.
| City | Last Spring Frost | First Fall Frost | Growing Season | Zone | Min Temp |
|---|---|---|---|---|---|
| Kansas City | April 6 | October 22 | 199 days | 6a | -10°F |
| St. Louis | April 2 | October 28 | 209 days | 6b | -5°F |
| Springfield | April 10 | October 20 | 193 days | 6b | -5°F |
| Jefferson City | April 8 | October 22 | 197 days | 6a | -10°F |
Planting Windows for Missouri
Based on average frost dates, here are the recommended planting windows for each city. The indoor seed start date is approximately seven weeks before the last spring frost. Transplanting should occur about two weeks after the last frost. The last direct sow date for fall crops is ten weeks before the first fall frost.
| City | Start Seeds Indoors | Transplant After | Last Direct Sow |
|---|---|---|---|
| Kansas City | February 17 | April 20 | August 13 |
| St. Louis | February 13 | April 16 | August 19 |
| Springfield | February 21 | April 24 | August 11 |
| Jefferson City | February 19 | April 22 | August 13 |
Gardening in Missouri
Missouri bridges northern and southern gardening climates, with the Ozark highlands in the south and prairie plains in the north creating varied growing conditions. Kansas City and St. Louis in zones 6a-6b have growing seasons around 200 to 209 days, ample for most vegetables. Missouri's soils range from fertile loess deposits along the Missouri River to rocky Ozark upland soils that need building up with organic matter. The state's humid continental climate produces hot summers and cold enough winters to satisfy chill-hour requirements for fruit trees. Tomatoes, peppers, sweet corn, and melons are summer garden standards. Fall gardens thrive with an August planting of cool-season crops.
Understanding Missouri's Hardiness Zones
Missouri includes USDA hardiness zones 6a, 6b. These zones indicate the average annual extreme minimum winter temperature for each area, which determines which perennial plants, trees, and shrubs can survive winter without protection. When purchasing trees, shrubs, or perennial flowers, always check that the plant is rated for your hardiness zone or a lower (colder) zone number.
Tips for Using Missouri Frost Dates
These frost dates represent long-term averages and should be treated as guidelines rather than guarantees. In any given year, the actual last spring frost or first fall frost may arrive one to three weeks earlier or later than the average. Factors that affect your specific location include elevation above the city center, proximity to water, slope direction, and whether you are in an urban or rural area. South-facing slopes and areas near large pavement or building masses tend to be warmer than surrounding open land. Low-lying valleys and exposed hilltops are often colder than mid-slope positions.
To protect against late spring frosts, keep row cover fabric, old bed sheets, or frost blankets on hand. Monitor your local weather forecast daily as the average frost date approaches. When frost is predicted after you have transplanted, covering plants in the late afternoon traps ground heat and can protect against temperatures down to about 28 degrees Fahrenheit. For fall season extension, the same covers protect mature plants from early frosts, often buying several additional weeks of harvest.