Before suggesting you anything, I would like to know following facts-
1. Your Gender- because the height is a factor which works differently for males and females. If you are a females, then there are less chances of increase in size at the age of 19 through natural remedies.
2. Your family details- like heights of your parents. It is because, this factor may get inherited from your parents genetically. In such case, you need to consult an endocrinologist who may suggest you some hormonal supplements which supports increase in height.
Apart from above mentioned points, healthy diet, out door games like basket ball, badminton, etc. will help you a lot.
Swimming, cycling, a good long walk also helps in height gain. You can also try skipping.
Living & Learning- simultaneous processes!