re: How do I make my grass grow slower?

This is a verticutter for a golf course


You may be able to rent something like this


Or get something like this for a push mower,


Now for St Aug I would just try a small spot and see how it does. St Aug has stolons, or horizontal growing stems on top of the ground. If you verti-cut too aggressive it could do some damage and make for a long recovery. I've never verti-cut st aug but it does wonders on bermuda.

Also you could try scalping it down once(cut at an extremely low height). Maybe worth a shot. And I would never fertilize St Aug with very much Nitrogen............ever.

And those rake looking things you drag with a mower are crap. They may work if you pass over your yard 100 times with it.