Spectrum and Ortho both make hose end sprayers with weed and crabgrass killer that won't kill your grass if applied before the temperatures are in the 90's. I've had varying success with it. Typically it will knock out the crabgrass for a while but about the time I'd need to reapply it, the temperatures are consistently in the 90's. It gets pretty pricy if you have a decent sized yard.
Cutting your grass at the highest setting is the best bet. Fescue blends will shade out some weeds if left tall. Crabgrass is tough to beat. Pre-emergent crabgrass preventers applied before the last frost will help keep it from germinating provided the soil doesn't get disturbed, so no raking of your yard once it is applied. Cutting frequently and leaving the trimmings behind is the best bet. Bagging and raking are unnecessary if you don't have clumping and visible grass trimmings on top of the grass.
After years of DIY treating my yard, I went with Tru-Green a few years ago. It is definitely making a difference in my yard. If I was willing to water it the yard might even stay green in our summer heat. I don't have any broadleaf weeds and for the most part, crabgrass is limited to places where the ground gets disturbed, like along the curb from edging. So far this year the only crabgrass I have is in my flower beds.
A fall plan to aerate and reseed your yard is your best bet. Top dressing your yard with compost after aeration can help improve the soil and give the new seed a better bed to grow in. The best defense against crabgrass is a healthy yard of turfgrass. This can be a multi-year process unless you want to roto-till your yard, improve the soil with truckloads of compost and plant sod. Compost works miracles in both sandy and clay soils.
