knowledge

There is no specific time for mool mantra. Whenever we get time is a good time to read and understand Gurbani.
ਜੇ ਵੇਲਾ ਵਖਤੁ ਵੀਚਾਰੀਐ ਤਾ ਕਿਤੁ ਵੇਲਾ ਭਗਤਿ ਹੋਇ ॥ ਅਨਦਿਨੁ ਨਾਮੇ ਰਤਿਆ ਸਚੇ ਸਚੀ ਸੋਇ ॥ AGGS 35
Je Vela Vakhat Vichareai Ta Kit Vela Bhagt Hoe || Andin Namey Ratia Sache Sachi Soe ||
ਇਕੁ ਤਿਲੁ ਪਿਆਰਾ ਵਿਸਰੈ ਭਗਤਿ ਕਿਨੇਹੀ ਹੋਇ ॥ ਮਨੁ ਤਨੁ ਸੀਤਲੁ ਸਾਚ ਸਿਉ ਸਾਸੁ ਨ ਬਿਰਥਾ ਕੋਇ ॥੧॥
Ek Til Piara Visarai Bhagt Kinehi Hoe || Mann Tan Sital Sach Sio Sas N Birtha Koe ||1||
If we continue looking for a specific perfect time and moment (Vela) to worship the God, then we will never be able to do so, because we will never find such a time. We should be attuned with the God every moment of our life. We should not forget God even for an instant. If we don’t forget God even for a single breath, then our mind (Mann) and body is peaceful (Blissful). Then we will be spending every moment, every single breath of our life according to the Virtues of the God.
For more info on such topics read my book Gurmat Doctrines (Part 1) available on amazon.com