College News

Instructor Vic Martin: Changing a Planting Map

Great Bend Tribune
Published November 25, 2023

As this is being written, the drought monitor report isn’t out.  Just east and south of our area some decent rainfall fell.  Our area, from reports seems to have around an inch or so and it tails off north and west of Barton.  While welcome it will do little to alleviate the drought.  Hopefully, enough to help emerged wheat and help some emerge.  The six to ten-day outlook (November 26 to 30) indicates a 40 to 60% chance of leaning below normal for temperatures and a 33 to 40% chance of leaning below normal precipitation.  The eight to fourteen-day outlook (November 28 to December 4) indicates near normal temperatures and precipitation.

We all know maps change.  Political boundaries for cities and even countries are a good example.  The map discussed today is different.  A map many not even be aware of unless you are a gardener, horticulturalist, or crop producer – the Plant Hardiness Map.  This map is produced by the USDA and was last updated eleven years ago and considers the period from 1991 to 2020.  In plain English, the map indicates winter severity and longevity.  It helps horticulturalists with determining what perennials are best adapted to survive winter and which won’t.  This map is used in some instances for crop insurance standards.  It’s useful in predicting the potential spread of insects, weeds, and diseases.  It’s a big deal.  So, did the map change for Kansas and if so, how?  As a point of explanation, the higher the number, the warmer the winter is.  For example, plants adapted for Hardiness Zone 7 have to on average be much less winter hardy than say Zone 4 or 5.

  • Overall, the state shifted about one half of a zone warmer.  We still have Zones 5 to 7 but 7 has expanded, especially in Southeast Kansas.  Here as in many things, Kansas is in the middle of things. 
  • This means for instance that the average growing season will be a bit longer.  Not the worst thing in the world for producers in Northwest Kansas.  And for landscapers, it means a slightly expanded variety of plants available, especially for perennials.
  • While it expands cultivated plant possible, there are downsides.  Plant diseases such as leaf rust in wheat can’t overwinter here and has to blow up from the south each spring.  If the trend continues it may overwinter here.
  • Many insects can’t survive winters here due to the cold and have to move in from other areas or “hibernate” in some form to survive winter.  It’s very possible down the road that at the very least, they will be active longer or can overwinter here. 
  • For weeds, it’s similar to other pests.  The overall point is the value of a cold winter.  Our current crop and horticultural practices are based on our winters.  A warmer, less harsh winter could potentially increase pest management costs among other potential downsides.
  • Finally, keep in mind we are taking about long-term climate here, not day to day weather.  Yes, we will likely see below zero temperatures and a polar vortex or two.  Yes, we can still have an early or late frost but overall, we are getting warmer.  We should be very concerned about this and this isn’t even factoring in changes in summer temperatures or rainfall.