I grew some pineapple tops just by putting them on the soil and they grew like crazy all summer, but the frost got them. It would be better to pot them up if you live in a frost zone.
I have been using coffee grinds for many years. They are pure nitrogen for your plants. They make everything grow fast. You can get them by the garbage bag full at Starbucks or any of the coffee houses. They love for people to recycle them.
If you're adding them to the pots, (the grinds), you don't want to add them too often. Like I said they are pure nitrogen. I would only add a small amount every 2 months and then water it in.
