I think I will not be doing any over seeding or slit seeding this year. On existing lawns that already contain 50% weeds I don't think it will have any effect. But replacing your normal fertilizers treatments by CGM could help I supposed, on the long term plan like you mentioned of 2 years. An also I believe CGM has 10% nitrogen in it. Not much but can help.
By putting down CGM every year, I will eliminate the seeds that later on become weeds, but for the existing dandelions, still no cure for them, since they are perennials. But for other types of weeds that spread by rhizomes and not by seeds, CGM is totally useless for those case.
I just wish they would bring back the Killex, 2 sprays applications and everything is dead. Just ban the stupid people that don't know how to use it. There is WAY more pollution and dangerous stuff happening in this world compared to a few pesticides
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