5a

In 2023, the United States Department of Agriculture updated its 2012 plant hardiness zone map to include changes in 30-year average annual lowest temperatures. The lower a zone's number, the lower the average annual extreme low temperature. Your zone helps you decide when to start seeds indoors and when to transplant starts or plant seeds outdoors to give them the best chance for success. While tender plants set out too early will probably survive, cold temperatures may stunt or delay their growth. Warm season vegetables need warmer soil temperatures for good germination and growth, too.

In 2012, La Crosse was solidly in Zone 4b, with an average annual extreme minimum temperature (1975-2005) of -25° to -20° F. But the 2023 update uses temperatures collected from 1991 to 2020, and La Crosse is now in Zone 5a, with average extreme minimums of -15° to -20° F. While the USDA argues against attributing changes to global heating, other climate research has accurately predicted a steady path of upward changes in global temperatures since the 1980s. Whatever, the reason, we're averaging warmer temperatures now compared with 15 years ago.

This means, the UW Extension Planting Guide for Madison, which was already in zone 5a, now works perfectly for La Crosse.

So, for the most part, we are leaning on the planting schedule suggested in that guide, whilekeeping an eye on actual conditions. We had a very warm early May, but this week, we've cooled down, a reminder to take a breather and not be in a rush, maybe.

Given predictions of rain and cool temperatures this week (May 19 through 25), we will not be planting at the City Hall garden on Tuesday, May 20. If it is rainy or wet, we stay out of the garden, usually to avoid compacting soil or spreading disease.

Check back here or email or text for updates on Hogan and Aptiv schedules this week.