When grass or sod is laid directly on top of clay subsoil it cannot grow deep roots. It will tend to brown out during dry times.
One client I did work at had purchased a new home with sod laid directly on top of subsoil. A year after they had taken possession you could pick the sod up like a blanket. It had not rooted into the clay at all.
- you need to have a minimum of six inches, twelve would be better, of topsoil in order for grass to grow. Keep in mind when ordering soil that the volume compacts by at least one third. Soil mixes containing a significant amount of organic matter such as compost or black earth will compact more than top soil.
- you need to consider drainage. Where can the water go? Where will it go without any intervention on your part? If drainage from your property goes into your neighbor's property and harms their property they can sue. Look on this site for your best friend, four inch drain pipe with sleevefour inch drain pipe with sleeve and french drainsfrench drains.
- consider using sod rather than grass. A little extra cost provides a way for the grass to establish quickly.
