Fibers elongate rapidly, up to about 16 days

That cell has multiple layers of cell wall.After a few days, the sides of the first layer,called the primary cell wall,stiffen, pushing cell growth in one direction and causing the fiber to elongate.The fiber elongates quickly for about 16 days.Then it begins the next stage: strengthening the cell wall.It does this by making more of the carbohydrate cellulose.Cellulose will make up 34% of the cell wall at this stage and swiftly increases.