Superb recipe to grow your hair two times faster -- How to use Red onions to help your hair Dice up 3-4 red onions and squeeze the juice out of them. You can also blend them, but the squeezing method is the preferred one. Mix a tablespoon of honey with the juice and apply the mixture of the scalp. Leave the mixture on the scalp for 15-30 minutes. Then rinse the mixture out with water. For more optimal results, leave the mixture on for an hour. Repeat the procedure for 3-4 times a month .