Installation to automatically carry out the loading and unloading operations of an apparatus able of opening the closed side walls of a plurality of crates (20, 21, 22, 23, 30, 31, 32, 33), preferably of horticultural products, provided with a bottom plane and with two couples of opposed walls, each of them being hinged on said bottom plane and being placed in an ordered and identical way, and vertically laid one on the other so as to form one or more stacks, said installation being able of carrying out the following operations: a) moving one or more stacks of closed crates (20, 21, 22, 23) in a first of receiving and loading station (S-1), b) opening and blocking the opposed walls of the crate placed on the top of a first stack, c) transferring an opened crate in a horizontal direction into a position overlying a stack of previously opened crates arranged on a second unloading station (S-2) able of generating a succession of stacks of opened crates (30, 31, 32, 33), d) and lowering said opened crate to the support level on the respective bottom plane, characterized in that said first receiving and loading station (S-1) comprises: - a first loading conveyor provided with a first loading end of said stacks of closed crates, - first support means adjacent to said first end able of engaging a pallet on which one or more stacks of closed crates (20, 21, 22, 23) can be deposed, - first handling means able of transferring by a translatory motion said stacks of closed crates (20, 21, 22, 23) from said pallet to said first loading end, said first handling means comprising a first pushing means placed in correspondence of the side of said first support means opposed to the side adjacent to said first conveyor, said first pushing means being arranged at a level slightly higher of the level of said first conveyor, and comprising a horizontal bar oriented preferably parallel to the direction of said first conveyor, said bar being provided with displacement means, preferably a properly motorized guide whereon an end (105-A) of said bar is made to slide on, said bar being able to be moved towards said first conveyor and away from it with a translatory and substantially orthogonal motion with respect to said first conveyor, said bar being provided with means able of making it to move into rotation according to a rotation axis basically horizontal and orthogonal to the bar itself, said rotation axis passing through said end (105-A) of said bar on which said motorized guide is engaged, so as to clear the passage over said first support means. a) moving one or more stacks of closed crates (20, 21, 22, 23) in a first of receiving and loading station (S-1), b) opening and blocking the opposed walls of the crate placed on the top of a first stack, c) transferring an opened crate in a horizontal direction into a position overlying a stack of previously opened crates arranged on a second unloading station (S-2) able of generating a succession of stacks of opened crates (30, 31, 32, 33), d) and lowering said opened crate to the support level on the respective bottom plane, - a first loading conveyor provided with a first loading end of said stacks of closed crates, - first support means adjacent to said first end able of engaging a pallet on which one or more stacks of closed crates (20, 21, 22, 23) can be deposed, - first handling means able of transferring by a translatory motion said stacks of closed crates (20, 21, 22, 23) from said pallet to said first loading end, said first handling means comprising a first pushing means placed in correspondence of the side of said first support means opposed to the side adjacent to said first conveyor, said first pushing means being arranged at a level slightly higher of the level of said first conveyor, and comprising a horizontal bar oriented preferably parallel to the direction of said first conveyor, said bar being provided with displacement means, preferably a properly motorized guide whereon an end (105-A) of said bar is made to slide on, said bar being able to be moved towards said first conveyor and away from it with a translatory and substantially orthogonal motion with respect to said first conveyor, said bar being provided with means able of making it to move into rotation according to a rotation axis basically horizontal and orthogonal to the bar itself, said rotation axis passing through said end (105-A) of said bar on which said motorized guide is engaged, so as to clear the passage over said first support means.