My gf grows a lot of flowers and another filipina told her to put pee on the plants. It works but you have to make sure they stay watered or the excess of nitrogen can burn the plants up. (my understanding is that it is the same as ammonium nitrate but I am not positive of that)
Same goes for Citrus trees, I can attest to that as I grew Orange Trees beside my house back in Oz and after years of slow growth, I was told to pee on them so I tried it peeing on them late at night, I was amazed as they started growing very quickly after years of very slow growth in the poor black clay soil. Gardening Australia - Fact Sheet: Citrus Trees Remember that urinating on the soil around lemon trees is beneficial to the plant.
I know MANY here eat Bananas so there will always be left over peels, tell her to also use shredded Banana Peels in her pots as well as on the garden as Flowers love the potassium! Banana peels can also work as a pest deterrent as well as adding crushed egg shells which I also do Using Banana Peels in the Garden for Fertilizer and Pests Kitchen Trash Your Garden Will Love