Water in fertilizer right away to avoid brown patches.

Yes, it’s probably fertilizer burn from not watering it in fast enough after application.

Nitrogen salts sit on the grass blades and suck the moisture right out of them, leaving those crispy brown spots. The fix is simple: water immediately after applying, and water deeply enough to wash the granules off the leaves and into the soil. If you’re using a spray-on fertilizer, same deal—water it in within a few hours.

Also worth checking what kind of nitrogen you’re using. Quick-release synthetic nitrogen (like ammonium sulfate) hits hard and fast, which is great for a quick green-up but also burns easily. Slow-release or organic fertilizers release nitrogen more gradually and are harder to screw up. If brown patches keep happening, switch to a slow-release formula and save yourself the stress.

Your lawn doesn’t need a big dose all at once—steady feeding works better.