Plant Hardiness Zone Movement Influencing Planting Dates

The US is getting warmer temperatures. And that’s affecting USDA guidelines. A new Plant Hardiness Zone report is out from the USDA advising farmers on how US temperature zones have changed. Chad Hart, agriculture economist with Iowa State University, says it’s based on average low temperatures in winter.

It’s mainly, I would say, targeted more towards gardeners than, let’s say, farmers themselves, but it links to what we see within the farm data as well. And we have been seeing those hardiness zones move to the north.

Aside from gardening, this report is a guide, Hart says, influencing how long the USDA views the growing season. Just this year the USDA updated early planting dates for soybeans for crop insurance purposes. Some sections, for example, may have moved down to April 10.

And those shifts are linked to what we’re seeing in the Plant Hardiness Zone data.

Expanding the dates give farmers more time in the planting season to get crops in the ground while staying under the cover of crop insurance. And Hart says that USDA window is updated sporadically.

What you’ve noticed, that you know if you’ve been watching over the past couple of decades, is we’ve been moving that planting window earlier and earlier because we have been seeing warmer conditions earlier which is linked to the data that we’re seeing in the Plant Hardiness Zone.

The Plant Hardiness Zone movement also allows for more opportunities. Hart says it all comes back to USDA wanting to make sure farmers are following good farming practices for the areas they’re in. And for some that could be double cropping.

As we shift these zones up, that means that we are seeing the weather conditions change that would fit more of, or have a possibility for, double cropping to be an effective marketing strategy.

This is the third report. The first was in 1990. The last came out in 2012.