This is an old article that has some wrong misleading points, like, "I-502 would still allow authorized patients to grow, use, and exchange pot under the existing medical-marijuana law passed by voters in 1998".
WRONG - there are several sections in thie intiative that change the mmj law.
Sec. 38. Sections 4 through 18 of this act are each added to chapter 69.50 RCW under the subchapter heading "article III - regulation of manufacture, distribution, and dispensing of controlled substances."
and then read Sec. 9 which is obviously included in sections 4 through 18
Sec. 9. For the purpose of carrying into effect the provisions of this act according to their true intent … the state liquor control board is empowered to adopt rules regarding the following:
(1) The equipment and management of retail outlets and premises
where marijuana is produced or processed, and inspection of the retail outlets and premises;
(2) The books and records…
(3) Methods of producing, processing, and packaging marijuana, useable marijuana, and marijuana-infused products; conditions of sanitation; and standards of ingredients, quality, and identity of marijuana, useable marijuana, and marijuana-infused products
(4) Security requirements for retail outlets
(5) Screening, hiring, training, and supervising employees…
(6) Retail outlet locations and hours of operation;
(7) Labeling requirements and restrictions on advertisement…

This intiative will make it difficult if not impossible to grow, and possess mmj in the state. There are so many regulations you have to be a professional business to make it work. Possession will be limited to 1 ounce not 24 as stated in the article.