Elridge from New Orleans, La writes
The Hi-Yield Weed and Grass Stopper can be applied in early fall and spring. Please click on the link here for the contact information for your local county extension office for specific times for application as they vary by region and these offices have the most up to date information regarding timing.
The general rule for spring is to apply your pre-emergent herbicide treatment after the ground has thawed from the winter but before the temperature of your soil reaches 55 degrees, as that is when crabgrass begins to germinate. Other weeds will germinate when the soil temperature is between 55 and 65 degrees. You can use a soil thermometer to determine the temperature of your lawn/area. You will want to measure the temperature of the soil a few inches below ground.
The ideal time to apply a fall pre-emergent herbicide to your yard is between August and November when the soil temperature is below 70 degrees and dropping.
Answer last updated on: 02/23/2024
