SIOUX FALLS, S.D. (AP) — Supporters of a pair of ballot measures that would legalize medical and recreational marijuana in South Dakota plan to launch their push Saturday to get on the ballot in 2018.

Backers of the South Dakota effort would have to submit nearly 14,000 valid signatures for each initiative to the secretary of state by November 2017 to put them before voters in 2018. The kickoff event is in Sioux Falls.

Melissa Mentele, founder and director of a group advancing the measures, said voters "should definitely expect to see us on the ballot."

New Approach South Dakota's medical cannabis proposal would allow patients with serious medical conditions and a health practitioner's recommendation to use marijuana. Qualifying patients — such as people with cancer, AIDS and hepatitis C — would be able to get a registration card to possess up to 3 ounces of the plant.

People 21 and older would be able to possess and use marijuana under the recreational marijuana proposal. Possession for South Dakota residents would be limited to 1 ounce of marijuana, five plants and any excess cannabis produced by the plants if they are stored in the same facility where they were cultivated.

Marijuana retailers could be established under the plan, which would also impose an excise tax on cannabis.

People who are serving time or have been convicted of a non-violent marijuana offense would have their cases reviewed or sentences commuted under the proposal.

Medical marijuana initiatives in South Dakota have failed at the ballot box at least twice since 2006. Last year, the secretary of state's office said backers didn't turn in enough valid signatures to get on the ballot.