IF you have removed all organic material from the area, and if you have scraped it down to undisturbed soil it will be fine but if you have levelled it with loose dirt it will need to be compacted.
The hill on the right side will be a water problem so I would gig out wider there so you can put a drain line around that corner and catch and direct water to a lower area.
I would also raise a concrete wall in that back corners to counter the dirt that will wash down against the building.
A 7" high wall can be framed up and poured at the same time as the deck.
I think gravel is a good idea and sheet poly under the slab.
The hill on the right side will be a water problem so I would gig out wider there so you can put a drain line around that corner and catch and direct water to a lower area.
I would also raise a concrete wall in that back corners to counter the dirt that will wash down against the building.
A 7" high wall can be framed up and poured at the same time as the deck.
I think gravel is a good idea and sheet poly under the slab.
