Question
Hi,

I am digging out some banana trees next to my cement patio. I noticed there is a couple of inches of river rock next to the cement. I was going to remove them because I am wanting to plant grass, but wondered if they are for drainage purposes? The dirt is heavy on the clay, and it does slant slightly towards the patio.

Am I ok to remove, or should I leave them and plant grass around?

Thanks

Answer
Hard to say, from a distance.  The rocks could be there just for decoration, or to catch the runoff of the patio and into a french drain of some sort.  If you scrape them off and they are only an inch or two deep, then go ahead and replace them with grass - they are just for show.  If however they go down into the soil significantly (8 to 12 inches) or you hit a pipe when you remove them, then they are there for structural drainage.  So, you'll have to probe down a little to see what is underneath.

As to grass on top of a gravel drain, I have installed it like that, but the grass above the drain is constantly dry (imagine that!) and requires more frequent watering to look good.

Hope it helped. ~Marc