If you are going to till you will want to give the soil time to settle. Roll, water,level,roll,water,level.......... When do you plan on doing this? If you still have Bermuda it is way to early to start killing it off. And once it does warm up it would be best to attempt to kill it numerous times. Weed killer,water wait a week or two then repeat. Wait another week or two and repeat. Bermuda does not like to go away. If it sounds like a summer long project it is if you want perfect results

Roundup X3 (water deeply in between) over a two week period, sod cut, remove debris, box blade to level, starter fertilizer, sod, then water x4 per day about 30 minutes until roots grab.
Done.

Do Not Till!

Thanks for your replies.

Neilaz - You suggest it's way too early to kill Bermuda. I'm in Georgia and it's greening up now. Are you suggesting that it's still not far enough into the growth period to take in the round-up?

Big Papi - you suggest to Not Till. Is this because you don't feel it's worth the trouble because the grass will do fine anyhow, or are you suggesting it will create issues (.eg. uneven lawn)?

It will create leveling issues that you'll be fighting for at least 4 years. Box Blading a yard is a one time and done kinda thing.
You generate extra work when you till. I've gone down that road.

The best time would be June. It is hot and growing fast. You will kill what is growing now but much of it is still waking up. Box blade is #1, doing nothing would be better than tilling

I am converting from fescue/common bermuda to Patriot bermuda this summer. The common is taking over my lawn and I want a nice bermuda if I am going to have it.

A PhD turfgrass extension/research specialist did bring up a very important point to consider. He suggested that I till to a depth of 4' to 6' and here is why.

He stated that RU will kill the top portion of the plant but not the rhizomes underneath the ground that are laying dormant. By tilling, it brings the rhizomes to the surface.

Upon doing this he suggested to wait 2-3 weeks after tilling. When/if the rhizomes begin to generate new shoots hit it again with another blast of RU or equivalent.

One thing he stressed, and others on this board have too. Hit the bermuda with a shot of nitrogen 2 weeks prior to applying RU to really get it growing. When you apply the RU hit it with Roundup Pro or generic equivalent and the full 4 quart per acre rate. He stated that if you merely make it sick it will not take in any more RU, unlike other herbicides. When the rhizomes begin to grow shoots hit it with the 3% solution of the 4 lb per gallon RU.

He stated that he once was unable to till on his property due to erosion issues and fought killing the rhizomes with RU for a long time since he was unable to till.

To be sure, I DO NOT want to till. But, given the tendencies I have experienced with my lawn, I am considering it. I once thought my neighbors bermuda was encroaching on my lawn, which it is in some areas. However, base on his information, I now think that some of the once-dormant rhizomes are a big reason why I now have widespread bermuda showing up and choking out my fescue. I have only lived here a year and can only speculate what the previous owner did. But, both of my neighbors have the same bermuda that I have and am left wondering if my lawn was at one time the same.

I do not want to till for other reasons too. But, if I have a choice to till and fight leveling or not till and fight this darn common bermuda I think I would choose to deal with leveling. This is just my opinion but I really want to do all that I can to get minimize it.

He did state that if the bermuda was not that widespread in my lawn then he would not see a need to till as he does recognize that there is a great deal of extra work involved. Given this, I guess each person has to make his own determination of what might be right given their own individual circumstances. That's what I am fighting with now.

It's pretty impossible to kill off bermuda entirely. Even if you kill 99.9%, that .1% will come back and take over.

I used RU 4 or 5 times before installing Sapphire St augustine. Bermuda still came back anyway. I'm just going to have to accept bermuda-st augustine mix lawn but bermuda won't be as dominant when trees are bigger casting more shade.

I don't see how you can maintain zoysia lawn that is known for slow growth without bermuda coming back from dead. Maybe since both are fine bladed, they will blend together and not stick out like a sore thumb?

Every article that I've read on the internet says to till the soil 4-6" as part of the preparation before sodding.

Then you must be new here. Because we've been shouting out against tilling for a couple years. Tilling is guaranteed to give you a bumpy lawn in 3 years or less. But I can see you are already going to till, so just take this as a differing opinion to what the expert says. We've been reading this forum for nearly 10 years and tilling is a mistake according to the vast wisdom of practical experience.

Wait until mid June before you attempt to kill bermuda. It has to be growing well and well fertilized.

I'm not so much worried about effort, or cost, I just want a lawn that I can cut to 1/2" should I choose to do so and have it look fine, even though I'll likely keep it between 1 & 2 inches.

What is this need to mow it down to 1/2 inch sometimes? If you have bermuda at 2 inches or even 1 inch and decide to mow it down to 1/2 inch, it will look brown and feel like needles under your feet. All you will have left is the stiff grass sheath. It will come back but why would you want to mow it like that?

I had forgotten about power rake. It's basically a mini tiller that gets down to 1-2 inches raking out all of dead grass. Getting rid of dead grass is another story.

dchall - Yes, I am new to the forum and would rightly fit into the category "knows just enough to be dangerous." With respect to seeing that I have already decided to till, you are likely right there, as well. I'm just having a tough time seeing how Zoysia would be as healthy sitting on clay as it would be on loam. I haven't removed the the clay yet, but I'm admittedly struggling to reconcile the vastly differing opinions on whether I should do so.

To take that a little further I'll almost bet you don't have clay. Here's how you can tell. Scoop a quart of dirt into a 2-quart jar. Fill it with water and just a few drops of soap. Stir it up, shake it up, and put the jar down on a flat table for an hour untouched. Instantly you should see a lot of stuff settle on the bottom of the jar. After an hour you can read the jar and see if you have clay. If you have water clear enough to see anything through, then you have no clay. Clay would remain suspended and make the water very murky. Rocks fall to the bottom first followed by sand and silt. Organic matter floats on the surface and in the water.

Why would I say this? Because you treat the issues different if you have real clay versus if you have very hard soil that acts like dried clay. It is sounding like a good soil test would be very helpful.

As far as bermuda and zoysia. I got a good deal on Meyer and had no time to prepare my lawn at all. Installed the zoysia over the bermuda. Left some gaps. The only bermuda to come through was in the seams and in a year it was crowded out. Obviously not the best way. Meyer is great in sun, shade or partial in my experience. You see all kinds of experts with completely different statements.