The easiest way for the home gardener to propagate a pineapple plant is by starting a crown. In fact, this is even the preferred method of commercial growers, just on a much larger scale. This is a great long-term project to share with your kids, who will be amazed to see a plant grow and thrive from the top piece of a pineapple, which is usually just discarded. To avoid disappointment, consider starting two pineapple plants in case you lose one of them.
Choose a mature pineapple with firm green leaves. A healthy specimen won't have any yellow or brown foliage. Reject fruits harboring scale insects, which look like small gray spots. Test for ripeness by tugging on the leaves. If any of them pop off easily, the pineapple is too ripe to be propagated. The skin should be dark golden to brown with very little, if any, green coloring visible.
Pull on some sturdy canvas or leather gloves to protect your hands from the stiff, spiny foliage. Grasp the pineapple's leaves firmly and give them a strong twist. The top of the fruit will come right off, bringing some of the stalk with it. Scrape away any bits of fruit adhering to the base of the stalk.
Use a sharp clean knife to cut a thin slice off the bottom of the crown. You're looking for a ring of small brown dots around the outer edge of the flat cut surface of the crown. These are baby roots. If you don't see them yet, cut off another thin slice. Keep cutting off very thin slices until the dots become clearly visible to you. Don't cut off any more once you see them.
Strip off about 15 to 20 of the lowest leaves from the base of the pineapple crown to expose about 1 inch of the whitish colored stalk. This is the part of the crown which will root. The lower leaves will only rot if left intact during the rooting process. There might be some small brown bumps where the leaves were. These are baby roots, and there may be some short little roots present that have already formed around the stalk. Take care not to disturb or injure any of these structures.
Set the pineapple crown on a paper towel or piece of newspaper on the counter out of direct sunlight at room temperature. Let it dry for 5 to 6 days to allow the stalk and the leaf scars to heal over and prevent disease from entering the plant. This also helps to prevent rotting.
Dust the roots and the entire exposed section of stalk generously with powdered rooting hormone. Cover the drainage hole of a 6-inch clay pot with a pottery shard. Add about 2 inches of small stones. Combine two parts bromeliad potting soil with one part Perlite and fill the pot to ½ inch from the rim. Plant the pineapple in the center of the pot. Firm the medium around and on top of the crown so that the lowest leaves rest on the surface of the soil.
Water just enough to dampen the soil so that the surface is evenly moist. From here on, be very careful that you don't allow it to dry out, but never allow the planting medium to be wet or soggy. Set the pot in a warm spot out of direct light, such as on top of the refrigerator. Pineapples prefer temperatures between 65 to 75 degrees Fahrenheit. It will take at least 6 to 8 weeks and maybe as long as several months for new shoots to begin emerging from the base of the pineapple crown.
Step the pineapple plant up to a 1-gallon clay pot when strong new shoots begin growing. Use the same process described in Step 6, but switch to a medium of three parts bromeliad mix to one part perlite. Water to evenly moisten the soil surface and place it in a warm spot near a window where it will receive as much direct sun as possible.
Move the potted pineapple plant outdoors after all danger of frost has passed. Place it where it will receive at least six hours of direct sunlight daily.
Feed the pineapple plant liquid fish emulsion or seaweed fertilizer once monthly, beginning four months after you potted it for the first time. Stop feeding and bring the plant indoors by mid-September, when it will stop growing for the season. Let it spend the winter months near the brightest window in the home.