Algae and Moss in lawns can develop with the following preconditions:
Overwhelmingly, the cause of rampant algae and moss in lawns in Melbourne’s southeast is OVERWATERING. Invariably, the householder has not dialed back the lawns watering requirement on the auto irrigation controller. For the winter months the auto irrigation controller should be off, perhaps with a manual watering once in a while.
To put it perspective, the evapotranspiration rate in winter is one–sixth of that in summer, turfgrass is in the low ebb of growth and we are generally inundated with showers through winter. Considering these factors, you need to manage against growing Algae and Moss in lawns.
The moss should turn black and shrivel up.
Note: Iron sulphate will stain concrete and tiles. Clean up with a blower vac or hose following application.