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Solving the short season conundrum

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ARTICLE SUMMARY:  Cover crops can be a challenge in short growing seasons. Learn strategies for making cover crops work in cold climates.

For those of us farming in northern climates, it can be a challenge to add cover crops. But even with short growing seasons, northern growers have figured out some well-tested strategies that allow them to benefit from the soil health gained from cover cropping. Regardless of which cover crop strategies you choose, probably the biggest hurdle to overcome is the trap of thinking only of the disadvantages—especially believing that others have an advantage over you so you don’t bother to get started. Here are two simple truths:

  1. There will always be another region/soil/grower who has some situation that is more advantageous for one way of farming or another. Does that mean we give up farming entirely? 

  2. Just because someone has a better situation does not mean we stop taking steps to improve the productivity of our soil while solving major agronomic problems. As I told my cousin a few years back… he farms in Illinois and asked me why I use cover crops when I have a shorter growing season farming corn and soybeans in Wisconsin. Even though I don’t have Iowa’s soils or Missouri’s climate, cover crops still makes sense for my farm, even if my application of them doesn’t look exactly the same as an Illinois, Iowa, or Missouri grower. 

So how can northern climate growers implement cover crops in short growing seasons? Here are a few strategies that are proving successful for growers already:

  1. Interseeding into corn at v4. Interseeding cover crops at this stage will not compete with the corn while allowing the covers to get a small start so they are ready to take off after corn reaches maturity (and sunlight once again reaches the ground) and after harvest. Some cover crops do better surviving the shading period than others. Northern growers have figured out they can mix the cover crop seed with topdressed urea at this corn growth stage, eliminating a second pass. 

  2. Drilling cover crops right after an on-time soybean harvest. Yes, I got specific on the timing here. In just about every northern climate, if you are able to harvest soybeans on time, you will have enough growing degree days remaining to germinate a drilled cover crop. Here again, using winter hardy varieties will make a big difference in seeing cover crop regrowth in spring. 

  3. Selecting winter hardy varieties for your cover crops. Some examples include triticale instead of oats, cereal rye, and winter canola. There can be a big range in survivability of non-winter hardy cover crop species. For example, tillage radish will survive down to around 18 degrees Fahrenheit, which means tillage radish can stay green until mid-November (at least in my area in Central Wisconsin). And, a forage collard will survive down to 10 degrees, which means it will get an extra three weeks of growth, providing more food for longer to support and grow your soil biology. 

 
If you can figure out the best way to weave cover crops into your operation, it can pay dividends. Cover crops can prove to be a valuable moisture management tool in the spring when trying to speed up soil warm up. Spring cover crop regrowth can drain and transpire excess moisture much more effectively than any tillage pass, especially on soil structures that have been degraded from years of tillage. And if the spring turns dry, you can always terminate cover crops sooner to turn off that tool. With improved moisture management through better soil structure, percolation, and transpiration, your fields will reach planting condition sooner in spring, thanks to your forethought and willingness to take action to improve your soil productivity and soil health. Don’t let a wandering eye towards your neighbors in the south discourage you and make you miss this great opportunity!

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