A lot of the crabgrass around here already has gone to seed.

I think your time would be better spent improving drainage so that your lawn does not stay moist or get access water through the addition of soil or soil ammendements or regrading. I don't use prepemergents yet I do not seem to have a crabgrass problem in areas where I have improved my drainage.

Pulling weeds before they go to seed certainly reduces the number of seeds for next year. If you are pulling it as the young plants come up, you are likely getting it before it seeds. If you waited a month and are pulling big plants out, they are probably seeding already.

As for it making a difference or not... that is debatable. The seeds can stay viable in the soil for years and years. Your current weeds could be coming from seeds that were formed a decade ago. The best defense against future weeds is using a preemergent in spring and growing as much, thick grass as you can. Seeds need a little bare spot to get going, so the thicker your grass, the less chance of weeds.

I applaud anyone who has the time and back for pulling weeds. There is no herbicide in the world that is as effective as hand pulling. If you get the roots, then that is 100% kill.

But as mentioned above a good thick lawn that is healthy is one of the best preventions around. I personally still use pre emergent products every season with a shot of fertilizer to help keep the lawn healthy.

I spent the better part of an 8 hour day last fall pulling all the mature crabgrass out of my KBG lawn hoping it would make the difference this year. It certainly has.

My lawn is now 3 years old and, like you, the first few seasons were really bad for crabgrass. As things filled it, it seemed that the crabgrass that was light green and thin the year before came back quite dark and very husky the following year. Even though the plants die off, the footprint they leave bare is just waiting for more crabgrass the next season.

If I had the choice, I would do it again. Get the 'bodies' out of the lawn and get some good seed in their place once cooler weather is around. The difference is well worth it IMO, YMMV.

Rob

I don't see anything wrong with your plan. I got half acer yard and was full of crabgrass. I started pulling crabgrass off in September. It is a lot of work, but I enjoyed it. I spent half hour before and after work. I am sure lots of crabgrass seeds had gone to the ground by that time, but they would not germinate until next Spring. I seeded lots of Kebtucky 31, and I didn't see much crabgrass in the spring. It is all about competition. Kentucky 31 germinates very well in fall and keep growing even in winter here. By the time crabgrass to germinate. (this spring), there wasn't space for them. My yard was taken over by Kentucky 31.

Good luck,

Kai