I recently did a backyard renovation which included rolling out new Sir Walter Buffalo turf (November 2023). The area sits on a clay base, so we decided to dig down 150mm and backfill with soil, to give the grass a better foundation. The lawn was initially doing really well and growing thickly.
However, recently I think I'm dealing with a pretty significant fungal infection. On reflection, this is likely due to me overwatering the area. At first, areas of the lawn began to thin out, with olive coloured spots appearing on the leaves. These worsened and then started to form brown patches all over the lawn.
After reading some advice on a similar issue, I have aerated the entire lawn and top dressed the brown patches with washed sand, as well as holding off on watering until the lawn is completely dry. I have also applied a round of Sulphate of Potash to the whole lawn (link) to try and speed along the recovery. This was applied about one week ago now.
Since applying the fertiliser, topdressing and aerating - the infection has not gotten significantly worse, but it hasn't really improved either. My main questions:
1. At what point should I look at applying a fungicide, if the mentioned treatment doesn't work?
2. Which fungicide should I apply and is there any risk in applying one when the lawn is so young?
Please see below pictures:
18th November - Clay base Dugout
18th November - Clay base dug out
18th November - Backfilled with Soil
18th November - Turf Layed
23rd December - Lawn Growing Well
8th January - Brown Patches and Fungus Pictures
Today (9th January) - Top-dressed and Aerated.
