Am 18yrs old, i want to increase my height so am going to take ashwagandha and homeopathy, my parents are tall, my growth rate has stopped at 15 why?,

Hard to say: The hormones that trigger puberty also push the final growth spurt and eventually cause the growth centers to close. A single x-ray of your wrist/hand can be evaluated for open growth centers. If they are open you can grow more, if closed, nothing you take is going to re-open them and permit more linear growth.If you stopped growing at 15 you are likely finished.