Arif,
My best suggestion for how to make a philodendron produce fruit is give it the seasons it evolved in. There is a rainy season high in nitrogen rich detritus soaked in mineral rich water from the rains sometimes every night for the whole night. By morning everything has receded, so the mix is incredibly well draining, & made of dried leaves on the top, composted leaves under this, dust, bugs living & dead, & humus underneath all of that, & then either a sandy or clay rich floor, & yes I know that is not clear. The important thing is in most places the roots of these plants never even reach the clay or sand. the detritus mixed layers that I have seen are between 6 inches & 2 feet thick. Note I said rains every night. Most of the time it is sunny during the day here from what I am seeing. Every night for the last month it has rained anywhere between 6 hours & the total night. Also something LariAnn figured out I suppose from trial & error or extrapolation from the location of the plants origins. These plants like warm rain water as that is what they get here. I am talking tropical warm, not boiling warm...
Watch my blog as I am keeping a photo record of the seasons in two locations close to me. This will help with causing your plants to bloom.
Most of the plants I see blooming here produced inflorescence during the dry season, but I am seeing Anthuriums producing inflorescence now which is the onset of the rainy season.
