No. Pre-emergent could harm newly formed roots.
Weed and feed is an herbicide and fertilizer combination product that is used to kill weeds and feed the grass at the same time. However, the timing of fertilizer applications generally does not coincide with the timing of killing weeds. Also, the herbicide ends up being applied to the entire lawn often to areas where it is not needed.
Seeds of broadleaf weeds occur naturally in all soils and can persist for 30 or more years. They will germinate when a lawn is thin, not healthy, or when the moisture content is suitable.
The seeds are brought to the surface by human or pet traffic, or when the turf is damaged or killed by drought, heavy traffic, insect feeding, disease activity, or are blown in from the wind.
Only if you are applying a pre-emergence herbicide to control crab-grass and other perennial weeds.
If you only have a few weeds in your lawn, simply spot-apply an herbicide rather than applying to the entire lawn. Apply just enough to wet the leaf and do not apply it to the point that the herbicide is dripping off the leaf. Make sure to apply to actively growing weeds.
Apply herbicides on a calm, clear day when the air temperature is between 50 and 85 degrees. Applying when temperatures exceed 90 degrees increases the potential for volatilization injury to other plants in the landscape.
Don’t apply if rainfall will occur within 12 hours. Also, avoid applying irrigation for at least 12 hours following an herbicide application.
Ortho Weed B Gon Plus Crabgrass Control or Spectracide Weed Stop for Lawn plus Crabgrass Killer are two products that have the broadest weed coverage and are easy to apply.
BioAdvanced Bermudagrass Control for Lawn has the best coverage.
Most weeds can’t tolerate frequent mowing. Also, when you mow too low, grass becomes less competitive and weeds will increase.
Correct watering is an important part of any weed control program. Watering deeply and infrequently (at least ½ inch twice weekly) is best for the lawn. This allows the soil surface to dry, which discourages the germinating of weed seeds.
Annual weeds produce copious amounts of seed. One crabgrass plant alone may set thousands of seeds each year. Many weeds compete with lawn grasses by spreading from a central point. They grow new plants for their crowns or send out runners.
This type of herbicide kills seeds as they germinate but has no effect on growing plants.
A pre-emergent must be applied before the weed seed germinates. For our region that is between April 21 to May 10.