Ola, P.R. dude
By fine soil do you mean in gradient or in quality?
If you mean gradient (as in size)
I suppose you can sift shovelfuls and seperate the fine soil from the coarse soil and use that if you'd like..Fine soil would have a very low retention quality and I don't recommend you use it unless you're willing to water your plant or crop like a gzillion times a day. Also it has little to offer in the way of nutrients.
Thats me being a smartass I know you mean quality.
The thing about backyard soil is that unless you've lived in that house or area for decades or what not you might not know whats been leached into the soil (i.e. parked cars oil leaks) also soils bought in garden stores or indoor gardening stores simply are of a higher quality and your guaranteed to not have any oil or other contaminants that might stress your plant or worst
. Furthermore your backyard soil might contain pests/molds/fungus that could inherently infect, eat and basically destroy all your plants and the work or if your lucky before you have done any.
I suppose you could treat your soil maybe sterilise it and add your own essential organisms, and while your at it you might as well pull the shit out of a cow pasteurise the manure
and so on and so forth, but that would be rather intrusive for the cow, not to mention how you feel about it.
My suggestion is that if you want to brew up your own soil type based on the characteristics of the strain you chose to grow or on the preference of how much time your willing to dedicate to your plant or crop you can FIRST and FOREMOST buy soil from a gardening store or indoor gardening store and then add as Parlabane has indicated Perlite, Vermiculite etc. till you've attained your desired soil quality.
Peace