I've always set the cut to 3 inches from advice on a gardening TV show and online reading about keeping a weed free lawn without chemicals. The idea being longer blades allow deeper roots, twice weekly 1/2 inch watering get the water deep in the ground beyond the reach (mostly) of the weed roots. Problem is that advice is dead wrong with respect to Zoysia and Bermuda, and has nothing to do with root depth. As for cutting height depends on the variety. The fine blade varieties like Diamond. Zoro. Emerald (looks like you have one of the finer textured varieties) should be maintained with a reel mower at 1/2 to 3/4 of an inch. The thicker wider leaf varieties like Meyers should be maintained between 1 to 2 inches. It is keeping them short that keeps them weed free, not letting them get tall, causing the grass to shade itself out, thin out, and allow weeds to grow tall and go to seed. When kept short the grass will form a very dense mat and choke out all weeds. Any weeds that do pop up cannot survive keeping their heads chopped off, weakening them, and not allowing them to mature and produce seeds. As for your watering has everything to do with root depth. Your method is tailored to force shallow root growth, not deep leaf growth. You are doing this by watering too frequently and too little water when you do water. Zoysia and Bermuda should not be watered until they show signs of wilt. Once they show signs of wilt, then they should be watered with 1 to 1-1/2 inches all at once to drive the water deep into the soil to 6 to 10 inches. Watering deep will encourage the roots to go deep to seek the water. The deeper the roots the less you have to water. The dryer it is on top the better because it deprives weed seeds from water and germinating. What you are doing is shallow watering, and too frequently. Only the top couple of inches will get wet and the roots will stay right there along with all the weed seeds getting all the water they need to germinate and grow. Here is a couple of pretty good links to reference too: http://www.clemson.edu/extension/hgic/plants/landscape/lawns/hgic1217.html http://www.turffiles.ncsu.edu/PDFFiles/000020/Zoysiagrass.pdf http://alabama-grass.com/View.aspx?Zoysia-Lawn-Grass-Maintenance http://edis.ifas.ufl.edu/pdffiles/LH/LH01100.pdf Note they are all saying the same thing I am telling you.

I would be a little concerned that you have no grass germination after 14 days. Tall fescue is a pretty quick germinater, 14 days is at the long end of time for it (unless it says differently on the bag of seed). Have you been watering your lawn 2-3 times a day for 5-10 minutes each time to keep the seeds moist? The Weed-B-Gone max is not going to help your new grass, it can only hurt. I'm pretty sure that it works by foliar absorbtion, so if you have no seedlings, it might be ok especially since it rained. The only thing your can really do anyway is wait and seed what happens, or overseed again. I would give it a week to make that decision.

You said "I also amended the soil with some composted cow manure." Perhaps that is contaminated. Look at this info http://www.puyallup.wsu.edu/soilmgmt/clopyralid.htm Also read about the bioassay, then do it to verify or not. Here is a link that might be useful: contaminated manures, etc

Hmm. And I see that you just became a member a few hours ago!