The time of Dhuha begins when the sun is about a spear’s length above the horizon and it continues until the sun reaches its meridian. It is preferred to delay it until the sun has risen high and the day has become hot.
The minimum number of rak’ahs to be prayed is two. The most that the Prophet (SAW) performed was eight rak’ahs. Umm Hani narrated that the Prophet (SAW) prayed eight rak’ahs of Dhuha and made the taslim after every two rak’ahs. (Abu Dawud)
From Abi Umaamah who said: "Allah's Messenger, sallallahu `alayhi wa sallam, said:
'Whoever prays the morning prayer in congregation then sits remembering Allah until he sun rises, then stands up ad prays two units of prayer returns with the reward of Hajj and `Umrah.'"
[Majma` uz-Zawaid of al-Haythami 10/104-105] Related by at-Tabarani and its isnad is good. Al-Albani declared it hasan in Saheeh at-Targheeb (1/464)]
'Whoever prays the morning prayer in congregation then sits remembering Allah until he sun rises, then stands up ad prays two units of prayer returns with the reward of Hajj and `Umrah.'"
[Majma` uz-Zawaid of al-Haythami 10/104-105] Related by at-Tabarani and its isnad is good. Al-Albani declared it hasan in Saheeh at-Targheeb (1/464)]
Let's practice the dhuha prayer.. =)
wallahu a'alam..