Here's A Trick To Test Corn Pollen In Your Fields

The 'shake test' may sound a little like a new dance craze, but it works

Published on: Jul 29, 2013

Bob Nielsen may not have a patent on the 'shake' test, but he's probably taught it to more people than anyone else ever has or ever will. And it's not a funky dance – it's a way to tell how well pollination is progressing in your corn field.

This is the perfect time of year to put his method to work. Simply pull an ear that you believe has been pollinated, and begin to carefully peel back the shucks. The goal is not to disturb the silks. Remember each silk is attached, or was attached, to a single kernel. Once fertilization occurs and an embryo is ready to develop into a kernel, the silk detaches from the kernel.

That's the crux of the shake test. If the kernels are fertilized, the silks are no longer attached. Once you unroll the wrapper leaves and get down to the ear and silks, your mission is to determine how many of those silks are still attached to kernels on the ear. If silks are still attached, fertilization has not occurred. Either you are checking early, or like last year, something has gone awry.

Shake test: Some of the kernels on this ear are pollinated, but not all. Some silks remain attached, especially out toward the tip. Fertilization starts at the butt of the ear and works out to the tip.
Shake test: Some of the kernels on this ear are pollinated, but not all. Some silks remain attached, especially out toward the tip. Fertilization starts at the butt of the ear and works out to the tip.

Fortunately, this isn't last year. Once silks turn brown, most of you should be able to do this test, shake the ear as Nielsen suggests, and the silks will fall away from the ear. This means that pollination and fertilization of the kernels has occurred. If silks remain attached, those kernels connected to those silks aren't pollinated yet.

You want to shake the ear gently, Nielsen typically recommends at field days where he demonstrated the technique. If you shake too vigorously, you may cause silks to detach even if fertilization hasn't occurred. A gentle shake will let silks that are detached fall away, and let those yet to be fertilized remain attached to the cob.

Try the test on your own fields soon.