Where can I get help for my son he is addictied to marijuana he is only 13 yrs old?

I smoked that from age 17 to 19, how do i say this-.... it completely opressed my inner light....constantly wanting or planning to get it when i wasnt on it or smoking it....it is a plant which means not as harmful as other drugs....yet to me- what i went threw with that- i felt like i was literally saved when life events led me to leave it cold turkey- and no im not religious,but it meant so damn much to me...i was so thankful i left. Thus- for some people it may be the way...but for me wanting to leave and not being able to somehow was a bit heavy for a young man. What im saying is maybe if you share some knowledge like this what others have gone threw and other online knowledge, or just better activities for your child to get involved with that dont involve such ways,he is definitely to young and to be blunt- doesnt need such a....tar ....on his inner temple- cause in fact it is a drug and heavy then a child can understand...i wish you well....peace