The pineapple (Ananas comosus) is a tropical bromeliad. Although there are several species grown around the world, 'Smooth Cayenne' is the one most commonly grown, both commercially and in the home garden. It takes two years, under ideal conditions, to grow a pineapple, and it is not always easy to tell if it is ripe for harvest.
Start watching the pineapple for signs of ripeness six to eight months after it emerges from the plant, which generally occurs a little over a year after the pineapple was planted.
Observe the color of the pineapple. When at least the bottom 1/3 of the fruit has turned yellow it can be harvested for canning. For fresh fruit, wait until the entire pineapple has turned yellow or gold.
Knock on the side of the fruit. If it sounds hollow, the pineapple is not ripe. A ripe pineapple will sound solid.
Smell the pineapple. Immature pineapples have no odor. A ripe pineapple will have that familiar pineapple smell.