PlantLife Online

Answer

There are a couple types of weed and feed products, one that acts as a pre-emergent and one that kills existing weeds. Pre-emergent herbicides act in the soil to prevent weed seeds from germinating, these are best used in spring and fall as warm and cool season weeds begin to germinate. Those labeled for use to kill existing weeds are commonly only effective on broad leaf weeds. The label for weed and feed fertilizers for use on broad leaf weeds most likely requires the fertilizer to be applied to a wet lawn, the moisture allows the herbicide to stick to broad leaf weeds.

Each brand has a little different directions to follow so read carefully, more is not always better. Unfortunately weed and feed fertilizer blends are not 100% effective.

Thanks for the question!