Yes, it would be in your best interest to do so.

Just as important as treating crabgrass now is using a preventative in the Spring. Consider using a chemical such as Dimension mixed with a spring fertilizer.

Thanks. BTW I did use Scott's pre-emergent last spring.

Scott's uses a relatively short lasting preemergent (pendamethalin), and if you apply it too early, it will not last into all of crabgrass season. There are other, longer lasting preemergents (dithiopyr, prodiamine) that will give you better protection.

If the crab grass is everywhere, I would nuke it now with roundup or some other non-selective herbicide (Don't bother with a selective herbicide like one that says it's for killing crabgrass or weeds since they tend to be much weaker than the non-selective). Get something that kills everything. Bare in mind that you need to be careful not to spray on shrubs or trees or anything else you don't want to die. Don't worry about killing grass that's mixed in with the crabgrass since you'll overseed that spot anyway.

In 2-3 weeks, everything should be dead and then you can scape the dead stuff away, put down tall fescue seed, lightly cover and begin watering. Mid to late Sept is the best time to start seeding in MD. Any sooner, it's too hot.

Thanks for the advice. I dont know much about grass types. Why do you recommend tall fescue? My yard is 1/2 acre of that a small part is nearly shaded all day. The rest is a mix of sun & partial shade. Which seed should i use in the shaded area? Thanks again.

One more question. Would anyone trust Lawn Doctor to do the reseeding? I was thinking of getting a quote just for the reseeding part, but doing the de-crabgrassing and cleanup myself. I am thinking of renting a powerseeder. Maybe Lawn Doctor can do it for just a bit more than me. IDK.