Hiya Clare. Yup, bought a regular supermarket pineapple, but instead of cutting the top off, I twist it off, hard to do but you are then left with a kind of core at the base. Next, leave it somewhere coolish, but not the fridge, for a couple of days to dry a bit, then peel of a couple of rounds of the bottom leaves. You should see baby roots around the base. Then twist it into a pot of compost. Depending on the size, you may need a couple of wee canes to hold it upright until the roots support it, water when dry, and heypresto! I have about 8 or 9 growing now, they are so easy, but some grow one MASSIVE plant, like the one that just fruited, and some shoot out baby pineapple plants, which half of my other plants have done. I have heard once they are 2 years old you can encourage them to fruit by stressing them for a couple of weeks - light and water deprevation really, but as I said, I didn't do anything, just let good old mother nature do her thing!
Now bananas are another story. They need gallons and gallons of water and feed. If they are stressed due to lack of either, they will not fruit. The banana plant is actually a herb!

my conservatory is begining to resemble a jungle! I shall have to bore you all rigid and take some pics!
