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Soil temps should dictate when to apply fall fertilizer

A soil scientist with the Minnesota Department of Agriculture says soil temperatures should dictate when to apply fall fertilizer.

Russ Derickson is based in Redwood County.

“We’d like to see farmers start applying nitrogen, or any type of nutrient source, after the soil has reached 50 degrees Fahrenheit or cooler.”

Waiting until soil temperatures are below 50 degrees increases the availability of nitrogen for next season’s crop, he says, while decreasing the amount of nitrate that could potentially leach into groundwater.

Derickson tells Brownfield the Department of Ag has a tool to help farmers check soil temps.

“It’s a webpage where you can link in to find out what the soil temperatures are at 21 real-time sites across Minnesota.  Every 15 minutes they’re updated.  So you can look at the daily peak and the daily low to get an average soil temperature.”

He says when the average temperatures are at or below 50 degrees, that’s when to start applying fertilizer.