If you apply a pre-emergent containing prodiamine, dithiopyr, pendimethalin, etc., you should wait at least 120 days before seeding. Siduron is advertised as safe for many cool season grasses, but the pre-emergent abilities, from my experiences, have been, meh.

This post was edited by yardtractor1 on Sat, Apr 12, 14 at 19:52

Your tall fescue sod most likely had a fair amount of kentucky bluegrass in so those spots will fill in. Unless your in western maryland I would go ahead and fert. now. Your not to late for pre-emergent but I would go with dithopyr that product will kill any crabgrass that has emerged already. If you must reseed you will need to use tenacity (mesotrione) as your pre-emergent. If by soil conditioner you mean the shampoo thing, I would skip it. Shampoo is a very short term wetting agent, and there are not a lot of native soils that need wetting agent. What's the reason you think you need to correct your " hard soil"?

I've been told that spraying Tenacity (mesotrione) works well as a pre-emergent (and will stop many more types of weeds than siduron which really only prevents crabgrass) but that the smallest quantity concentrate you can buy is $90 per bottle. Is the granular form mesotrione less expensive and just as good at protection as the spray-on?

I don't see any reason at all to believe that KBG is in your grass at all. I do see some Creeping Bentgrass in there though.

Key point, You said you had sod QUALITY seed, NOT sod. Advice will vary greatly knowing this.

I would use Tenacity as a pre-M and it will kill out your Creeping Bent when applied 2 times at 2 week intervals and most importantly, at half rate. May take three passes, but it wipes that stuff out! Pay attention to where the grass looks bluish and dewy in the AM when the good grass is dried out of the dew.

That said, on to the next post. Tenacity does not cost 90 per bottle. Not even close. Closer to half that, and is far cheaper oz. per oz. of specialty and big box chems that don't do 1/10th of what it does.

BTW, if you feel there may be KBG in there, look up Poa Annua. That is far more likely.

This post was edited by gsweater on Sun, Apr 13, 14 at 22:27

Where are you finding your tenacity cheaper?

Do a search for Tenacity. Amazon, which typically sells considerably higher than others has it for 66 with free shipping. I got mine at Lesco year before last at 54 dollars.

Others on the forum may tell you where you can find it locally on the cheap.

Thank you all for your replies. Re: correcting hard soil, I'm a newbie at most of this, I just thought the lush feel of a lawn was also due to soil that has not compacted. In some sections, there is even evidence of "cracking" in the soil. Blending all of the advice together, I'm trying to get rid of creeping charlie, fertilize, and reseed but I understand it is unwise to weed-and-feed. Would an approach to reseeding only and applying herbicides later in September work? Is there such thing as new TTTF strangling out weeds?