I don't know if it is fail-proof, but after I removed the bottom leaves, I let it dry out for about 4 days. Then I just stick the bottom 1/2- 1 inch into moist potting soil and wait. Water into top occaisonally. Good luck!

Probably the best results I have had with growing pineapple tops is by twisting the top off of the fruit and letting the bottom where the fruit was removed dry and callus, usually this takes from 3 to 4 days. After the bottom has dried and callused you should remove some of the base leaves to reveal several small brownish and sometimes white bumps, these are the roots, many times you will even have larger roots that have already formed. This is where I believe many people make there mistake, when you plant the top in soil, make sure that the soil is slightly moist not very moist and not wet, then take the top and just place the base on to the soil, not in it, I made the mistake when I first started experimenting with pineapple top by covering the whole base with soil, usually my result would come out to a top that had all its leaves dying and eventually a non growing piece of compost. Your probably saying, how can the top hold itself up, well it cant, so what I would suggest would be to start your tops in styrofoam cups that are filled part way with the soil and then prop up the tops in the cup. Now what you want to do for the next month or so is, nothing. Leave the top alone, except to occasionally check if the soil is totally dried out, if it is then water it sparingly, but don't at this stage water it in its crown, that makes them rot very quickly, especially when there in doors. After about a month, if the leaves have not totally died and turned brown, then you know that the top has possibly taken root, don't get worried if the tips of most of the leaves turn brown. Wait another month before you repot the top, these plants take a very long time to grow so be prepared to wait until there established into a nice looking plant.
Good Luck!
Algreen

I have rooted lots of pineapple tops without one failure. What I do is cut about an inch of the actual fruit below the leaf portion of the pineapple. Then i get a pot of finished compost and put the top rite on top of the soil, pushing it in just enough so that it won't fall over. After that I just water the crown and keep the soil moist. it sounds like you might not have the temperature warm enough for it to root. I would recommend bottom heat like a heating pad. DO NOT let the temp get below 75ish, or it might grow roots so slowly that it will dryout before it has a good hold. Because I am blessed w/ good Florida weather i just stick em in the ground and let go. here is a visual of some of the pineapples I have rooted

Here is a link that might be useful: pics 30-32

It seems we all have different methods that work.

I started 2 pineapples last year by simply twisting the tops off, removing some of the smaller, lower leaves, cuttin away the protrucing piece of the fruit that is left on the bottom after twisting it off and placing it in water.

In my water I used a rooting hormone, with RO water, and occasionally when I changed it I used fertilizer. It sprouted roots after only a few days and I eventually planted them outdoors. Of course I just killed the second of my two pineapples the other day, but that's another story...

Sam

I have gotten mine to root in about a week and a half. Cut the fruit off the crown. Then remove the leaves at the base revealing around an inch or less of stalk. Let the entire thing callus over, now that the juicy leaves have been taken off of the base already. When the cut bottom is sufficiently hard and dry, with the stalk starting to brown a little bit. Stick this in a glass of water so that the entire leafless base is underwater. Change the water if it gets discolored or anything. Roots form quite readily this way-within the first week, small root nubs will have already begun to form.