Water coming into garage from outside when it rains, no basement
Change the grading so that the garden area is lower than the garage floor and slopes away from the building by at least 1/8 inch per foot (or "1 %", as 1/8 inch [1/96th of a foot] is very nearly 1/100 of a foot.) 
Or make it 1 centimeter per meter if that suits your local practices better. Try to maintain that slope away from the building for at least 12 feet or 4 meters.

I should perhaps say "fix" rather than "change" as I consider what you have to be evidently incorrect, if all-too-common.