I understand that deep watering is best 2-3 times a week for newly planted chilean mesquite, but nowhere can I find reference to how much water is required for 'deep watering' I have (2) 2 gal/hour drips on the tree now about 15 feet tall but the leaves seem to be yellowing. I would like to know about the quanity of water it needs to have to optimize growth (it is February in Phoenix) Thanks