Just make sure its a nice tight fit. The underside of the astro turf is quite rough. If he finds a way to get underneath it, it will, over time, effect his scales.
I use to use astro turf in my enclosures until one day I noticed two of my snakes looking like rhinos. The rougness of the astro had rubbed their scales on their nose till they were rough, and raised. I am a hopeless cutter. Couldn't cut straight if my life depended on it. So I switched to marine carpet which looks just as good, but with a softer underside.