Looking at both the calendar and weather forecasts, frost-seeding is no longer a viable option to add red clover into a wheat stand. We can’t count on good freeze/thaw cycles to create those honeycomb conditions in the soil that create good seed to soil contact.
The option left is to broadcast clover seed over the wheat stand. Successful establishment still depends upon getting good seed/soil contact. Growers need to evaluate soil, weather and stand conditions to determine if a straight broadcast operation is worth their time, effort and expense.
Evaluate the wheat stand. How dense is the stand? Can broadcast clover seed get down to the soil surface? How much soil is visible? A research study at North Carolina State University compared red clover seed broadcasted at 1.5-inch or lower vs. 3-inch high forage.
The plots with 3-inch high forage had reduced clover seed germination and establishment. What is your field soil condition? Many soils around the state are saturated. This is not a desirable seeding condition. What is the weather forecast?
Unfortunately, the reality for many wheat stands is that the window of opportunity to broadcast red clover is rapidly closing.
For those stands that still have limited top growth, have bare soil between rows, and are on non-saturated soil with good drainage, broadcasting red clover seed may still be an option. Consider the use of broadcasting seed using an ATV to increase timeliness on fields that are wet.
Although we do not know of any replicated research trials to support this, some farms have reported success with adding red clover to their liquid nitrogen top-dress applications.
A Penn State Extension publication on management of red clover as a cover crop includes the following statement, “An effective method of frost- seeding red clover is to mix the inoculated red clover seed with liquid nitrogen fertilizer and top-dress the mix onto winter small grains in March or early April.
“It is important to minimize the time that the seed and inoculant are in the fertilizer solution to maintain viability of the seed and bacteria. Therefore, mixing the seed with the fertilizer solution at the field is recommended. Since peat-based Rhizobium may clog up the sprayer, using a Rhizobium solution instead is recommended.
“Typically, flood nozzles are used, and screens are removed. Make sure the nozzles have an orifice large enough to keep them from becoming clogged up.”