PINELLAS COUNTY, FLORIDA - Helpful information about Pinellas lawns & landscapes.

Brown Patch is a Cool Weather Disease in St Augustine Lawns

Brown Patch in St Augustine Turf
Brown Patch causes a temporary discoloration of St Augustine turf

Those brown circular patches in your St Augustine turf grass lawn are probably brown patch. Brown Patch forms distinct circles or joined lobed circles of dead leaves with a “halo” of yellow grass. It does not kill the turfgrass, only effects the leaves. The results is a "bad haircut" look to the lawn.The pathogen is a soil born and can not be eliminated. The Good News: Except for the worse cases, Brown Patch can be controlled with good cultural practices! With the cooler temperatures and wetter soils, Brown Patch is active in lawns in St Petersburg, Largo and Clearwater areas.

Cold vs. Deadly Disease

My experience with Brown Patch has me categorizing it as a “cold” as opposed to a “deadly disease”. I think the “cold analogy” is a good one because:

  • Brown Patch generally will not kill your grass – unless it is near death to begin with.

  • It is a temporary condition – Brown Patch thrives at moderate soil temperatures and as the soil temperature rises (or lowers), Brown Patch will cease to be a problem.

  • Many lawns are not effected by Brown Patch, and others have chronic problems with Brown Patch (not everyone catches a cold).

The causal agent is part of the environment – it is a soil born disease and cannot be eliminated. Since it is not life threatening, I manage the Brown Patch with biological methods to reduce occurrences and treating only severe occurrences with commercially manufactured fungicides.

What to expect from Brown Patch

Brown Patch is a cold season disease of fall and spring. Brown Patch forms circles and/or lobed circles of tan/green weak turf that is flattened – like a round weight had been placed on the turf. The rings start out fist size and can grow to be 20 feet in diameter or larger. The outer edge of the ring (active area) is a multi-colored, mainly yellow in color, and is very distinct. Brown Patch responds to fertilizer - especially readily available nitrogen – by getting worse and to potassium by declining.

Also expect St Augustine to fully recover when cultural conditions change – i.e. the weather warms or cools.


Since the disease responds to fertilizers and is not lethal, manipulating fertilizers is the best management practice for controlling Brown Patch. To reduce the impact of Brown Patch during the cool season months, I use slow release organic sources for nitrogen in very sparse amounts and high amounts of potassium. Manipulating fertilizer elements is “biological” control – and biological controls are very “green” in practice but slow to develop and weak in performance. Therefore in severe cases I will use a commercially available fungicide as a curative measure. In the 500 or so lawns I service, I only have about 5 that are problematic for Brown Patch and require fungicides; therefore the manipulating of the fertilizer elements is a good management practice for controlling Brown Patch.

Article by Rick Orr
APL Lawn Spraying Inc.

Rick Orr is the creator of, an Agronomist and the Owner/Operator of APL Lawn Spraying. Rick is a graduate from VA Tech in Agronomy (Turf Ecology). He has been a Golf Course Superintendent, Certified Arborist, Landscape Contractor, Irrigation Contractor and Adjunct Professor for Environmental Horticulture.

Rick is an expert at growing St Augustine turf. Since 1995, Rick has spent his time researching, developing and testing the best management practices for St Augustine turf grown in Pinellas County.

The results of that work is a one of the top rated lawn spray companies in Pinellas County – APL Lawn Spraying. APL Lawn Spraying is a family owned business serving residential and commercial properties in Pinellas County, FL.

APL Lawn Spraying provides lawn spraying to commercial properties, HOA’s and single family homes. To request a free quote for your property, click here: Free Advice or Price Quote

Speaking Engagments - Does it seem like you are only hearing one side of water restrictions, fertilizer bans, plant restrictions and many other urban landscape hot topics? Rick Orr is available for speaking engagements for your HOA, Community or Professional Association or Garden Club about a variety of subjects. Call or email for more information.

Facebook Twitter YouTube Pinterest

Visit the Author's Website