When spring arrives, I can’t wait to work in the garden, but when is it too early?
The USDA hardiness zone map breaks the United States into zones based on average minimum winter temperature. That is, the coldest temperature we are likely to see each winter, on average, for a given location in the country. This is critical information for choosing landscape trees and shrubs since winter cold is one of the main determinants of where plants can survive.
In Michigan, our hardiness zones range from 4a in the western Upper Peninsula and northern Lower Peninsula, to 6b in the southeast and along the Lake Michigan lakeshore. Chelsea, Michigan is in zone 6a (-10 to -5 F).
Each winter, on average, the risk of frost in Chelsea is from October 5 through May 4.
Almost certainly, however, Chelsea will receive frost from October 19 through April 19.
It is almost guaranteed that Chelsea will not get frost from May 20 through September 21.
Our frost-free growing season is around 154 days.
Here is a terrific resource on when to start and/or plant seeds based on the last frost date https://awaytogarden.com/when-to-start-seeds-calculator/