If Crabgrass or other weeds do get in your lawn, spray them with Bayer Lawn weed and crabgrass killer, just be sure its not over 85 degrees or your lawn will burn

Clay soil is definitely a challenge for us in the TriValley area... Clay is Alkaline so it's high on the ph scale. Rototilling acidic soil like composted redwood and builders sand and/or gypsum into the soil will help separate the clay particles and soften the soil for better root penetration and will help get plantings the nutrients they need and lower the ph so a

more broad range of plants can grow and thrive 

Great customer and contractor relationships equal great work and service... 

The best way to manage weeds is to PREVENT them... Pre-emergent prevents seeds from germinating

Apply in February (when you plug aerate your lawn), May, and August, then reseed your lawn in November when the chemical is no longer active.