A lever controls each of four chambers which can be activated to rapidly duplicate the tall flowers within. These can be turned into red, yellow, magenta and pink dyes.
From the warp, go left through the tunnel and go past the chicken farms. It is near the bone meal farm.
How to use the farm
Flick the switch above the flower you want, and place as many bone meal in the chest beside the lever as you would like flowers. Remember to turn the lever back off when you are done.