Not far from the Ginger Farm, I don't know if you know. If you don't know I recommend to try their smoothies, they are original and good.

That being said I will move to the North of Chiang Mai from next month and I didn't see weed shops there at the moment.

(Oh shoot, after checking Google map I have seen 2 not far from my next apartment).

What I really enjoy in Thailand is that everywhere I go nobody smokes, it is quite a big change compared to Japan where everybody smokes around.