news NEWS Open-air weed grow with 5,000 plants illegal, even in Canada: RCMP Grow on mountainside in remote area of B.C. discovered and dismantled. By Angela Stelmakowich Image of grow on mountainside. / Photo: Twitter, credited to RCMP It’s perfectly legal for Canadian adults 19 and older to grow as many as four cannabis plants in a residence for personal use, but cultivating 5,000 pot plants on a B.C. mountainside is simply pushing things too far.