Question
Tom,
My builder only brought in one load of topsoil for over 10k sq. ft of lawn.  I live in Logan (northern), Utah where the summer weather is hot and dry.  I have Kentucky Bluegrass and parts of it won't even grow in the summer because it is on top of hard clay.  I am about ready to aerate the lawn again this fall and was wondering what I should bring in to spread over the lawn and fill the holes.  Should I bring in a load of sand/soil, only sand, compost?

Answer
Scott:

I assume that your home and yard are fairly new.  Building a good soil for turf and landscape will require years.  Do not give up easily.

The most productive soil amendment I have ever used was compost.  A high quality material will not only furnish nutrients, but also build the topsoil layer (A horizon) by introducing helpful bacteria and fungi.  There are a myriad of other benefits, but these are the main ones.

Twn thousand sq. ft. should require ten cubic yards of a high quality compost.  If you aerate, a good idea, then apply the 3/8 inch of compost over your seed.  No fertilizer of lime is needed.

For supplier, look for a professional manufacturer or broker.  They should also have an analysis.  It should have 1-3 parts N, 2-5 parts P and 1-3 parts K, with micronutrients.  This amount is approximately five tons (plus), which will give you what would appear to be too much N-P-K.  But these are slowly released and held in the biological package until needed.

Compost is an elixir for bluegrass.  You may do this every fall until the lawn performs as expected.  Then, the quantity may be reduced.

Sand is a good additive.  I have used it to level and topdress after the lawn is established.

Best wishes.