Answer: Grassy weeds are the most difficult to eradicate in turfgrass. That's because weed and feed is formulated to kill broadleaf weeds but not grasses. If they killed grasses, they'd kill your lawn, as well. So, digging the weeds, roots and all is one permanent solution. You might dig one up and take it to your cooperative extension office or Master Gardener clinic for identification. Once you've identified it you may be able to find a herbicide specific to that weed that won't harm your turfgrass.
Thatching or plugging can be done now, or anytime through about the middle of October. If you dethatch, rake out all the debris and then reseed your lawn and keep it watered. The new grass seed will germinate in 7-10 days and your lawn will be renewed by the end of the summer. If you aerate instead of dethatch, you can leave the plugs on the lawn. They will dissolve with rain or sprinklings from the hose.
Best wishes with your lawn!
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