YOU NEVER NEED TO TILL. Oh, sorry was I shouting? You never need to till in preparation for grass. I'm short of time here at lunch so I'll just drop that and leave it without explanation. Don't let the bobcat guy on your lawn. If he can come up with a real tractor, then fine, but bobcats take 10 times longer to do the grading job as a tractor with a box blade. A tractor can do that job in 15 minutes to an hour. A bobcat might take a week. It would be best if you could rake the dead stuff up. You want good contact between the bottom of the sod and the top of the soil. Roots will not grow through the air looking for soil. Gotta run, but I have more to say. If you want to ask more questions, go for it.

Sod is a lot quicker. Zoysia seed is not that hard to grow and a lot cheaper than sod. I did have some small issues with crabgrass. But that is because I put the seed down a little early. I got my seed from http://www.supersod.com/grass-seed/zenith-zoysia-seed.html I also used http://www.soil3.com/cubic-yard-compost and the grass did come in faster where I used it. If you do seed you will want to wait till mid spring. Plugs can take a while. Zoysia is a very slow spreader.

here are few more photos these are in my backyard. seem like the same plant. 1st one is 7 inches tall and the other 2 photos seems like the same plant but fully matured.

From the WSU extension service publication: "Kentucky bluegrass is the most commonly used lawn grass in the United States. Kentucky bluegrasses, in general, are not well-adapted to western Washington’s soil and climate." From OSU discusson of seed blends suited to PNW lawns: "Kentucky bluegrass is the most common lawn grass east of the Cascades, but disease susceptibility makes it poorly suited to locations west of the Cascades." And from article written by Tom Cook, Professor Emeritus, OSU on Poa pratensis (KBG): "Kentucky bluegrass use in the Pacific Northwest reads like a ‘Tale of Two Cities’. In areas east of the Cascade Mountains it has always been the dominant turfgrass. With a climate defined by hot summers, low humidity, cold winters, and calcareous soils, bluegrass grows incredibly well. West of the Cascades, bluegrass has been tried repeatedly without much success. The first major effort to use Kentucky bluegrass in western parts of Oregon and Washington started around 1960 when sod production began. Following the lead of sod growers around the USA, farmers planted mixtures containing ‘Merion’ bluegrass to increase sod strength. Early plantings were noted for their susceptibility to Stripe rust. They typically failed in 3-5 years being replaced by indigenous grasses and often with annual bluegrass. Gradually, people quit trying to plant pure Kentucky bluegrass and today you will generally find bluegrass only in seed mixtures marketed nationally and in some sod blends." Despite what some east coast responders may erroneously assume, KGB seed or seed blends are NOT recommended for this area!! Local seed mixes - and regionally prepared mixes are highly recommended over national brands - rarely include any in their blends and local sod farms do not grow it. The climate and growing conditions of the PNW are pretty unique, especially west of the Cascades, and it is highly unusual for anyone who has not lived or gardened there to speak to them with any kind of knowledge or accuracy.