Spring is just around the corner and that means it is time to be thinking about pasture fertilizers and weed control. As you all know the last 3 years have been hard on our pastures due to drought. One major question that seems to get asked a lot is “did my grass survive”. The short answer is only time will tell.

Research has shown that January and February are recommended times to fertilize pastures and hay meadows, but many producers have been known to wait till March and even April. As with most agricultural practices there is more than one way to do things, it is just a matter of adapting to the timing of the application.

Many know producers are aware that they need nitrogen for cool season grass such as fescue. While that is true for hay production especially, for pastures phosphorous plays an important role in plant health especially in a drought year. This is due to phosphorus promotes strong root development and early root growth. Phosphorus also plays a key part in cell division during growing stages, storing and transferring energy, and increase disease resistance in plants. So yes, grass needs nitrogen but also requires phosphorus to maintain a healthy pasture.

There are options available for weed and brush control that can be applied by coating your fertilizer with them. This is beneficial to you as a producer for a couple of reasons. Most importantly time your time! Why wouldn’t you want to save time by doing two things at once? AKA feeding your grass and killing your weeds in one pass. Secondly by doing this you also save money by not having a second application cost. The down side to this is you will need to wait till later in the spring to apply the herbicides to get a better control on your weeds. It is recommended that you wait till April 1^st to make sure weeds and brush are emerging and are actively growing quickly. This also helps with the residual in herbicides maintain control longer into the fall such as Aminopyralid plus Rinskor.

If you choose not to use a herbicide with your fertilizer and would like to over seed your pasture you can mix the seed in your fertilizer cart and spread it together. Now the thing you need to know about doing this is that the seed will not travel as far as the fertilizer. To overcome this it is best to find 50 foot double spinner fertilizer buggy, and then you’ll need to set it to half of the application rate. You will then double spread it to reduce your seed skips.

As for recommended fertilizer rates a soil test is your best option to see what is needed in your pasture, but there are some common mixes that many producers tend to use. For lower stocking rates on pasture a lot tend to use a 30-30-30 (Nitrogen-Phosphorus-Potassium) mix. For higher stocking rates a 50-30-30 tends to get a little extra bump to get them though the growing season.

On March 25, 2025 there is a Soil Health: Pasture Rejuvenation field day at the Southeast Research and Extension Center in Parsons from 8:30am to 2:30pm. Lunch will be Provided. Topics include: Soil Variability, Soil Health Measurements, Pasture management, Farmer Panel, and Drone Demonstration.

Lonnie Mengarelli is a K-State Research and Extension Agriculture agent assigned to Southwind District. He may be reached at [email protected] or 620-223-3720

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