Dormant Fertilization

Dormant fertilization is one turfgrass management practice that I believe is vital for a successful upcoming season.  I have been a big fan of dormant fertilization throughout my entire career.  My definition of dormant fertilization is:  fertilizing when temperatures have dropped sufficiently to stop top growth - basically, when mowing has ceased. At this time, however, root growth can still be active.

What fertilizer is best for dormant fertilization?  There are many choices, but for 40+ years of golf course management career I have used the natural organic Milorganite.   Milorganite was my go-to fertilizer for all dormant applications.  Each fall when top growth stopped, we fertilized the entire golf course with Milorganite. 

Alway a great time of year when the dormant Milorganite application goes out!

Always a smile on my face when spreading Milorganite.

Greens, tees, fairways, and rough all received between 0.75#N/M-1.25#N/M.  Even today, as a consulting agronomist, it is the single most important fertilization practice I recommend and discuss with clients. I do get questions on why Milorganite.  So, let’s discuss the reasons why it’s such a great fertilizer and why it’s particularly great for a dormant application.

First, Milorganite has been in business for over 90 years. That is some kind of staying power. Some of the reason for that is the consistency with the manufacturing of this product.  In my 40+ years of using this material, I have never opened a bag that had an issue - truly remarkable. To have a better understanding of the production of Milorganite, check out this great video link, HERE. 

The consistency in the manufacturing of this product is truly amazing!

Second, Milorganite may be the most researched fertilizer in the world. So, why is it such a great dormant fertilizer choice?  First, as an organic, it is very stable and leaching concerns are non-existent during fall/winter.  So, from that aspect, it is very environmentally safe and gives great piece of mind. From a turfgrass plant use, the real key to dormant Milorganite is all about nitrogen mineralization.  Consistent research results show that microorganisms responsible for the mineralization of the organic nitrogen in Milorganite remain active even in frozen soils.  The percent of nitrogen mineralization throughout the winter period has been shown to be in the 15% range.  This has been documented multiple times through university research.

Possibly the most researched fertilizer ever!

So for example, if you apply 1#N/M to your fairways as a dormant application, there will be 0.15N/M available immediately to the plant after snowmelt.  Nitrogen availability, along with the iron content, will produce tremendous spring green-up without any flush of growth.

Early spring fairway green-up.

Early green surface green-up.

This nitrogen availability will easily be 2-3 weeks ahead of any spring-applied fertilizer. The remaining nitrogen fraction will be released during the growing season to help with the peaks and valleys of a conventional fertilizer release curve. So, it’s that time of year to set yourself up for next season – using Milorganite as dormant fertilization will certainly be a big help!  Milorganite is a fabulous choice for dormant fertilization.