When you think of growing bitcoin safely, you get very few possibilities. Also it needs long time to grow compared to the methods which involves high risk factors. Upon ones need can decide which method to be chosen for growing hard earned bitcoin.
Because the title says "any safe way to grow your bitcoins" , it's take more time to make it "grow" if you don't take a risk.
But you must make an adaptation with a risk , so you can feel your bigger earning through "risk" action.