This is a regular query – how many days to put cotton garland to Lord Ganesha? There are no specific rules regarding this but the generally followed pattern is 7, 10, 21 or 42 or 108 days.
The best option is 21 day. This will help in desire fulfillment. It also helps in overcoming troubles and stoppages in life and activities.
The best day to start putting garland is Tuesday and Chaturthi (the fourth day of a fortnight).