choosing between sprinklers and direct watering

i have about 400 plants growing outdoors having trouble with the cool night ive been watering direct in the holes in the afternoons my question is ive heard that watering with sprinklers may inhibit flowering or that the buds wont grow dense at all theyll be all bushy does anyone know if these is true id rather water with sprinklers i could leave them on 24 hours theres a stream thyat goes by i have about 300 mts of hose going down hill to the spot have no trouble with people im growing in mexico could use any input thanks