Hi Marilyn
The soil is dry and therefore little can live there for now, but once the roof is off and you have some organic matter on top, then give it a good water, I reckon that life will return quickly enough for you to start growing as soon as you have done that.
Buying topsoil is not worth the money, often it’s been stacked for long enough that most life has gone out of it, so you are gaining nothing. Your own compost which will have had some good soil organisms eg on weed roots, will be more beneficial.
