General Care & Feeding
Light and temperature
A pineapple is a tropical plant and frost or freezing temperatures will kill it. If you live in a temperate climate, your pineapple must divide its time between your house and your porch or garden.
Pineapples like to get at least 6 hours of bright light each day. During summer, set your plant on a sunny porch or bury the pot in your garden. Do not take your plant out of the house until all danger of frost is past. When you first remove your plant from your house, keep it in a semi-shaded spot for several days to prevent sunburn.
During cold months, keep your plant in the house. Bring it in early in the fall, by mid-September. Place it near a window or sliding-glass door for maximum sunlight. At night, move it away from the window to prevent freezing. The pineapple prefers a temperature of 65 - 75 degrees F (minimum of 60 degrees). If the room is warm enough for you to be comfortable, the pineapple will be at the right temperature.
You can also grow your plant indoors, for example in a basement, by using "Plant-Gro" fluorescent light tubes. This light can also be helpful if your windows do not let enough sunshine into the room where you are keeping your plant. You should keep the light on for between 12 and 14 hours per day. When the plant gets large enough to bear a fruit you should reduce the day length to 10 to 11 hours until the inflorescence appears in the center of the plant. You can then return to longer days.
Watering and fertilizing
The pineapple plant is miserly with water, requiring only about 20 inches of natural rainfall per year, if well distributed. You need only wet the soil once a week, and when the plant is indoors, it is best to apply all the water to the soil. When outside, spray the leaves in addition to wetting the soil so that the cups at the bottom of the plant are filled. It is also important that it never completely dries out. Then again, it must never sit in soggy soil. During its growing season, it will appreciate more water than in the winter months.
Fertilize carefully and only about once every month or so during the growing season. If using a solid plant food, scatter it on the surface of the soil and wash it in by watering.
A liquid (foliar spray) fertilizer can also be used. Pour the solution into the base of the leaves and on the surface of the soil. Take special care not to pour the solution into the center of the plant as the young leaves may be injured. Follow directions under "small shrubs" given on the label of the products you use.
Pests and diseases
As house plants, your pineapple will be subject to a minimum of pests and diseases if given proper care. The pests most likely to attack your plant are mealy bugs, scale and mites. All can be removed by washing the leaves with soapy water, rinsing after with clear water. Or, spray with an insecticide. Be sure to follow the directions on the label when using insecticides.
The only disease you would likely encounter would be heart rot caused by fungi. In heart rot, the central leaves turn black and are easily pulled out of the plant. When heart rot occurs, the plant can sometimes be saved by pouring a fungicide into the heart (center) of the plant. If this stops the infection, a side shoot will start growing. This shoot will then become your plant and will eventually flower and form a fruit. Or you can remove it and begin a new plant.
Flowering and Fruiting
Although the pineapple plant is attractive in and of itself, most growers want their plants to flower and fruit. In Hawaii, a crown takes about twenty to twenty-six months to produce a ripe fruit. However, it may only take twenty months, and you will see some surprises along the way. When your plant is at least 24 inches tall and twelve to fourteen months old, an inflorescence bud will begin to form in the center of the leaves. You will not be able to see the developing fruit until about two months later when it will surprise you with a bright red cone emerges from its center. For an excellent photo log (Plog?) of one enthusiast's success with growing a fruit, click here.
(By the way, to the right you can see very healthy baby pineapples growing at Longwood Gardens, in Longwood, PA. There were a total of 8 plants in the room. Clearly they have a system that works!)
After twenty months come the flowers. Bright blue flowers open row by row, starting at the bottom, over about two weeks (flower development in Hawaii typically occurs in late December or January when the days are short (about 10.5 hours) and the nights are cool (55 to 65 F; about 13 to 18 C)). Each flower only lasts one day, but there are many to enjoy.
When the petals of the last flower have dried, the fruit begins to develop. After three to six months from this period, your fruit will begin to ripen. When the fruit is golden halfway up, your pineapple is ready. Surprisingly enough it will be just about the size of a can of pineapple, or a bit larger.
If your pineapple plant is at least 24 inches tall and has not flowered by the time it is twenty to twenty-four months old, you can "force" it with a few different techniques that trick the plant into putting its energy into flowering instead of making new leaves.
Forced Fruiting
It is best to force the plant to flower during the winter months when the days are cooler and shorter as this is when a pineapple is accustomed to making fruit.
The first technique is to lay the plant and pot on its side between waterings. This interferes with hormones in the plant, causing the production of another hormone, ethylene, which induces flowering.
A second method of inducing flowering is to place the plant in a bag with two ripe & bruised apples for two weeks. Move the plant to a shady location during this time, and then move it back to its sunny spot. The ripening apples produce ethylene gas that will induce flowering in the pineapple.
A third method is to place a small lump of calcium carbide about the size of your little fingernail in the center of your plant and pour a quarter cup of water over it. This will release acetylene gas that will force your plant to flower. To improve your chances of success, it is best to treat your plant in the evening after the sun goes down and temperatures are cooler. (Calcium carbide may be obtainable at a welding shop, garden store, pharmacy or toy store.)
Two to three months later, the plant should form a flower spike in its center.
Harvesting your pineapple
When your fruit is about six months old, about four months after flowering has occurred, changes begin to occur. The color of the shell changes from green to rich gold. The color change of the shell occurs first at the bottom of the fruit and moves upwards.
During this change, the fruit becomes sweeter and the color of the flesh changes from white to yellow. The fruit will weigh from two to four pounds. When the fruit is golden half way up it can be picked and eaten, though if you wait until it's fully ripe it will be worth the wait! Once the fruit develops, it should last on the plant for several months.
