you're soppose to grow tall naturally, but a idea that is NOT A WISE DECISION FOR YOU TO MAKE is to stretch yourself.
how tallbeanstalk can grow
It really depends, you may not grow at all, grow a few inches, or grow a ton! You might be able to figure out by knowing how tall the child's parents were when they were that age, and see how tall they were when they were 18. If you can't figure out how tall they were when they were 18, see how tall they are now. People usually stop growing at the age of 18, so that could also give you a good estimate. This also depends on the gender, as boys typically grow taller than girls.
18 feet
Amaryllis plants typically grow to be about 18-24 inches tall.
Bell pepper plants typically grow to be about 18-24 inches tall and 18-24 inches wide.
Sweet pepper plants typically grow to be around 18-24 inches tall, with a spread of about 12-18 inches.
You will grow until you are about 18-19 years old. How tall you are is set by DNA. Take a look at the people in your family and see how tall they are. You will be the mean between them. This should give you an idea.
Typically, between 13 and 18 hands high at the shoulder.
Dill plants typically grow to about 18-24 inches in height. However, some varieties can grow taller if they are given the right growing conditions.
It varies on age and person. Girls stop growing at the age of 18.
Time will tell, and you will soon know.
At 18 I would not hold my breath waiting to grow 3 inches.