Gauge question….. my gauge is 10cm = 18 dc and 8 rows = 10cm. 

My 18 dc matches. But my rows do not. What do I do?  How do I adjust?

Question on blocking. I am making my first garment. The fiber is cotton/bamboo and is machine washable. The pattern says to block but I have also been told that blocking isn’t as important when fibers are machine washable. So…. Block or not?