As a junior in high school I had the privilege of going on a mission trip/choir tour to Costa Rica with my church. We stayed at a Methodist mission camp there, which was surrounded by pineapple farms. I had never seen a pineapple grow before, and not even thought about how they might grow. If you had asked me, I probably would have guessed that they grew on a tree similar to a coconut. But I would have been wrong.
Pineapples are actually the fruit of a bromeliad (Ananas bracteatus). You know, bromeliads are those short, spiky plants that tree frogs like to sit in. Most of them have beautiful blooms of bright red, pink, purple, orange or yellow.
[caption id="" align="aligncenter" width="350" caption="Common Bromeliad plant - photo courtesy flickr member Jofel Tobias"][/caption]
I remember going to the Myriad Gardens in Oklahoma City on a school field trip when I was younger and we were told about the rain forest and about how many bromeliads grow up in the trees (epiphytes) and the center of the plant holds water, where the tree frogs would lay their eggs. Now that I am a plant and aquarium fanatic I know that bromeliads are the staple plant for terrariums/paludariums/vivariums for people who keep tree frogs.
Bromeliads (in general) are fairly easy to care for. They prefer humid environments and like to stay wet in the middle but don't require a lot of light. You can just check on them every once in a while and pour some water into their center if they have become dry.
Want a free bromeliad? Well, it's not entirely free... If you ever buy a pineapple at the store, save the crown. You might notice that the crown itself looks a lot like a bromeliad. It is!
I'm not sure how you normally pick out your pineapples at the store, but if you plan to start a plant from one, you will want to get one with a nice looking top. (The leaves at the top of the pineapple are the only ones you will see for several months.)
Starting a pineapple bromeliad
The first step is to remove the crown from the pineapple - like so.
[caption id="" align="aligncenter" width="450" caption="Step 1: Lop off top of pineapple, leaving a little bit of fruit attached"][/caption]
Next, cut away ALL of the fruit, even with the bottom of the leaves. True, you could just do this in one cut, but I usually don't prepare the pineapple top when I cut the pineapple for eating. I usually leave some fruit attached to the top for several hours - maybe even a day or two - moving to step 2. It is important to remove all of the fruit. The fruit can cause the rest of the pineapple top to rot, if left attached.
[caption id="" align="aligncenter" width="450" caption="Step 2: Carefully remove all fruit from pineapple top, cutting just below the lowest leaves."][/caption]
Next, peel away several layers of the bottom leaves, exposing the stem. I would suggest at least 4 layers of leaves all the way around. You really can't pull away too many leaves. Now you will notice some little root starts. If your pineapple sat for very long before you prepared it, these roots might be as much as a 1/2 - 3/4 of an inch long. Otherwise, they are probably just little nubs.
[caption id="" align="aligncenter" width="450" caption="Step 3: Peel away several layers of leaves, leaving a bit of stem exposed from the sides and some root nubs showing at the bottom. In this case, the root starts are very small."][/caption]
Place the crown in a plastic cup or glass. The remaining leaves should hold the pineapple crown in place. Fill the cup with water until the exposed stem is in the water, but the leaves are more or less above the water level. The crown should not be placed in full sun while it is rooting. I actually stuck mine on top of the refrigerator, which is pretty dark except when the kitchen light is on. Light is not really necessary at this stage.
About once a week I would replace the water, as it will get stinky if you don't. When you're changing the water, check to see if any of the lower leaves are starting to turn brown and rot. If so, just peel them away. This will help prevent the rest of the plant from rotting. Within a couple of weeks you should see real roots growing to several inches in length.
[caption id="" align="aligncenter" width="450" caption="Roots beginning to form from pineapple base"][/caption]
In some cases, the pineapple might be reluctant to put out many roots while in water. If yours has been in water for over a month and you have little to no root growth, you might want to go ahead and plant the pineapple head. However, if roots have not formed and the head has turned mushy, you need to just throw that one away and try again with a new pineapple.
Many bromeliads are planted in peat moss only. I potted my pineapple plant in a rich potting soil with some vermiculite added in. I water it about as frequently as my other tropicals and it been happy for about three years, growing long leaves out of the top.
[caption id="" align="aligncenter" width="500" caption="Established pineapple plant with significant new growth"][/caption]
I think it is pretty rare to have a potted pineapple plant produce fruit in temperate climates, but it doesn't keep me from growing one. Who knows, maybe one day it will surprise me!