The negative effects of the black layer are most evident during summers like the one we are experiencing now – prolonged periods of hot humid (wet) weather. The black layer forms within the soil profile, primarily on putting green rootzones comprised primarily of sand. The cause of the black layer – sulfur, or surface sealing of the rootzone by algae – is extremely detrimental to turf growth.

The black layer is often detected by a pungent odor when a sample is taken and a quick smell is taken. The difficulty with the black layer during our current weather conditions is that the layer becomes anaerobic. The lack of oxygen and the development of undesirable gases results in rapid root loss, contributing to a decline in the turf. The problem with an anaerobic zone is that the plant is not producing enough energy (via respiration) to maintain growth. 

To minimize the impact of the black layer, quadra-tining into the layer to promote oxygen exchange would be recommended. Additionally, if the turf begins to turn yellow an application of foliar nitrogen or iron may help.