I have purchased a Poinsettia which had bright red leaves , but the fresh leaves are not having colors. What should i do to get colored leaves.
It will begin produce colors in the late fall, in response to longer nights. Around that time you can put it in an unused (unlit) room - some people even let them spend time in the closet every day - so your evening light in the house isn't disruptive.
Do a search here for poinsettias; I bet there's a whole bunch of info!
I see that you are from India. When did you purchase your Poinsettia? Give us a little bit more information and maybe we can help.
I purchased it this febrary 2011. i kept in a pot near my bacony, where it gets morning sunlight, my main door faces east
Since you purchased it that long ago, and with full red bracts, you can assume that the flowering period is over. Some people are really good at prolonging a poinsettia's 'red' stage by avoiding warm temperatures, providing some good light, etc. It is not unusual, however, for the plant's bracts to drop off as the new growth emerges.
That new growth will be green.
You will have to induce flowering again in order for another display. The actual flowers of this plant are the tiny sticky yellow things in the middle of the red bracts. Flower induction is usually done once per year.
At that time, which should be after about 9 months of good growing conditions, the plant needs about two solid months of 'short day' treatments. This means that your plant should be exposed to very good light for about 11 hours and uninterrupted total darkness for 13. This can be accomplished by sticking the plant in a dark closet sometime in the early evening and pulling it out thirteen hours later.
No peeking, no lights or the cycle will need to start over again from day one.
Quite honestly, most of us consider poinsettias a temporary holiday visitor. Even if we are able to get them to flower again, we can't duplicate the display that the original growers are able to achieve with their hormone applications, special lighting, etc.
Be sure to let me know if I can answer any questions.