The Mughal Gardens of Rashtrapati Bhavan (President's House) were open between February 16 to March 28 in 2008. Security is tight - this year visitors were advised not to bring water bottles, briefcases, handbags and ladies’ purses, cameras, radios and transistors, cell phones, umbrellas, or eatables. It is a beautiful garden of course, and very popular, but I prefer Lodhi Gardens. If you do want to see a Delhi garden, then go to Lodhi in the morning at 7 a.m. You will enjoy not only the gardens, the monuments of the Lodhi Dynasty, but also the sight of morning walkers, joggers, people doing yoga, or a Laughter club that laughs its way to fitness. After a walk through the garden, you can eat breakfast at Khan Market.

My wife and happened to be in Delhi in Match and visited the Mughul Gardens. As Deepa said, they have tight security, and you just cannot stop at any point and linger, without the security guards inside noticing it and telling you to move along. My impression is of a very pretty, well laid out garden with flowers blooming in springtime. I'm sure you can get the dates when it is open next year on the net.