I am relatively new to lawn care - I attempted a lawn renovation on my home in the fall of 2017 with moderate success. The lawn came in relatively strong (Connecticut, mostly sunny & flat landscape). Before reseeding I tilled the land and added 4" of fresh topsoil, but I didn't achieve full coverage in the fall. I decided in the spring of 18 that it made more sense to overseed and focus on thickening up the lawn rather than using a pre-emergent. Unfortunately this plan backfired. As soon as the summer weather hit my lawn went completely dormant and an indescribable amount crabgrass emerged. I tried using Quinclorac to control it but that only seemed to slow it down. In the fall of 2018 I hand picked every last blade of crabgrass from the lawn and reseeded once again. It was at that time I did a soil test and realized my PH was 5.5. I have been able to get it up to 5.8 so far, and just applied lime again (should be around 6.0 after this app). My dilemma is choosing between successful overseeding (I have a dog who tore the lawn up over the winter), and using a powerful pre-emergent such as Prodiamine or Dithiopyr. My current plan was to use Tenacity so I could seed and prevent crabgrass, but I am starting to have second thoughts. I put Tenacity down last weekend when soil temps were about 50 degrees. From what I understand I would need to reapply Tenacity every 3-4 weeks until late summer in order to prevent crabgrass. I am okay with this strategy if it allows me to successfully overseed this spring & fall, but if I end up with a crabgrass issue as bad as last year I will regret not using Dithiopyr (I think its too late for prodiamine now). Any thoughts on using Tenacity as your ONLY pre-emergent? I have some other pesky weed in the lawn as well that I would like to get rid of. Its only in one area of the front yard but I am starting to see it pop up in small sections of the remainder of the lawn. It doesn't look like clover to me - any ideas on what this is as well? Thanks all.