Pineapples (Ananas comosus) are tropical plants, belonging to the bromeliad family. Very slow-growing plants, pineapples can take between 1 1/2 to 2 1/2 years to fully mature. Once a pineapple matures, only then will it blossom and set fruit. Pineapples are warm-weather plants, hardy in U.S. Department of Agriculture plant hardiness zones 10 through 11; they are intolerant of cool weather. If exposed to cool weather, it can take even longer for the plant to mature, flower and set fruit.
Growing a pineapple plant from the top of a mature fruit can take upwards of 2 1/2 years before the plant is mature enough to blossom. If growing from suckers, it can take 1 1/2 years, and from slips, roughly one year to maturity. After that, you need your pineapple plant to flower, and then wait another six months before the fruit is mature enough to be harvested and eaten. If your pineapple plant has been exposed to poor growing conditions, including cooler weather, it can take even longer for a plant to mature and blossom, and for the fruit to mature enough for harvest.
As a member of the bromeliad family, pineapples can be forced to flower once the plant is fully mature. If your plant is at least 2 1/2 years old and has not blossomed, cover it with a plastic bag, sealing it shut, and place an apple inside the bag with the plant. Leave it covered with the apple inside for four days in a sunny location. The apple releases ethylene gas, which encourages bromeliads to flower. From here, it will take roughly two to three months for your pineapple plant to blossom.
Pineapples, in addition to needing warm temperatures, are very drought-tolerant. They have a wide range of soil tolerances and can withstand slightly alkaline and acidic soils. However, pineapples need well-draining soils. While they need sunshine to thrive, they do best in partially shaded areas, as direct sun exposure in high temperatures can burn the plant and the fruit. Pineapples prefer a relatively humid environment, around 50 to 70 percent humidity, and a draft-free growing area.
Pineapples can be grown indoors or outdoors, but because of their limited tolerance for cool weather and their requirements for a humid, breeze-free environment, they are most commonly grown indoors as a novelty plant by home gardeners. When fully mature, they have 24- to 30-inch-long spiky leaves, and reach 1 to 3 feet in height. Because of their size and growing requirements, indoor pineapple plants are best suited for greenhouses or conservatories. Additional benefits of growing pineapples indoors are that you can protect it from any possible drops in temperature and keep it away from most pests. While pineapple plants are hardy, they are still sensitive to certain pests, namely mites, and mealy bugs.