Watering in preemergent.

The label on the pre-emergent will state water in with at least 1/2 inch within 2 or 3 weeks of application (or something close to that). Personally, I’ll set a sprinkler for 45 minutes and do another 45 minutes later in the day.

And with no rain forecast for a while and discussion on the H&G board of applying fall pre-emergents, it’s important everyone to remember the pre-emergent herbicide will not do its job unless watered in either by rain or lawn irrigation.

The time of your sprinklers is not the measure to use, it’s the amount of water. As said usually about 1/2”, but I put out some grub killer Dylox I believe that asked for 1.5”.

It depends on the water output of your system.