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Hello!! Recently I've started to notice large patches of yellow grass forming on my lawn. When I look closely at the dead yellow grass I can see spots of grey. The areas where the yellow grass have died has now left bald spots on the lawn. Can you please advise on how to best save my lawn ?
Welcome to the Bunnings Workshop community @Garden_novice. It's brilliant to have you join us, and many thanks for your question about lawn care.
A good first step is to check for lawn grubs and beetles. You can do a simple test by mixing a squirt of dishwashing detergent into a litre of water and pouring it over the edge between the dead and live grass. If grubs or beetles are present in the soil, they should surface within about 30 minutes.
From what you’ve shown, yellow patches with grey spots and exposed roots often point to grubs eating the grass roots. If your test confirms grubs, you can treat the lawn with a suitable lawn grub killer. If no grubs appear, then the cause might be something else, such as physical damage or localised soil issues, but grubs are the most common culprit for sudden, patchy die-off like this.
Please let me know if you have any questions.
Mitchell
Hi @Garden_novice, thanks for coming back with an update, and you’re very welcome. You did the right thing by testing for grubs, and if none surfaced, I would not recommend applying a lawn insecticide at this point as it is unlikely to help and could be unnecessary. However, you mentioned spraying the solution, and it needs to be poured, and the area needs to be flooded. This ensures it penetrates deep enough. Spraying it is not sufficient.
Based on what you are describing now, particularly the grey spotting, the grass pulling away easily with no roots, and the way the patches are spreading, this is much more consistent with a fungal disease rather than insect damage. Fungal issues often show up during periods of humidity, warm nights, overwatering, or poor drainage, and once the roots rot, the turf will lift straight out exactly as you’ve noticed.
The next step is to stop any regular watering for now and only water if the lawn is clearly dry, ideally in the early morning, so the surface can dry quickly. Improving airflow and sunlight to the affected areas will also help slow the fungus. I would recommend treating the lawn with a lawn fungicide, making sure to follow the label directions carefully. This will stop the disease from spreading, but it will not revive the already dead patches.
Once the fungus is under control, rake out the dead material to expose the soil, lightly loosen the surface, and top dress with a sandy lawn underlay or soil. You can then reseed or lay small patches of new turf, keeping it lightly moist until it establishes. A light application of a lawn fertiliser after recovery can also help the surrounding grass thicken up and fill in over time.
Here are some helpful step-by-step guides: How to lay turf and How to grow a lawn from seed.
Mitchell
