Roots showing??!!

ok my plants are about 3 months old, and on a couple of them i can see what appears to be white roots coming out of the bottom, but slightly above the soil but going into the soil....i didnt know if that was a bad thing that i could see them...and if so should i add more potting soil to cover them??....

 

I would just to be safe.

 

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ya ive got it in a pot outside...........

 

I`ve got some indoors in pots and have found one is doing the same thing I plan to cover the roots with soil.......