The girls reacted badly to the drugs and, with the aid of parents, the school nurse and deputy principal, had to be admitted to the emergency department at Waikato Hospital.
Their behaviour caused such concerns that the hospital's security staff were called to help control them.
Marfell's lawyer, Louis Wilkins, sought a moderate community work sentence for his client, saying she did not supply her daughter with the drugs.
"The important thing here is she did not supply these to her daughter ... These are most unfortunate circumstances."
"She has made significant effort since then and has attended counselling with her daughter."
But Judge Noel Cocurullo said he was not impressed. Marfell had "at best" a "problem with making responsible decisions".
"The example of you allowing your daughter to smoke and keeping these pills are examples of when you needed to apply to more responsible decision-making processes.
"It's hard for me to see there's a degree of responsibility around her when she didn't know what they [the pills] were - she should have destroyed them," he said. "Your 14-year-old daughter has regular access to your handbag to share cigarettes ... You need to change your mindset by not supporting a 14-year-old smoking ... You can, in that regard, provide proper guidance."
Judge Cocurullo said the fallout from the students' drug-taking was tragic and serious but within the charge there was no allegation of supplying drugs made against Marfell or any commercial need on her behalf.
Fairfield College board of trustees chairman Jonas Hapuku said the 14-year-old girl was stood down from school for the rest of last year following the incident and was referred to Youth Aid.
"As far as I'm aware I'm not sure where she is now," he said.
Mr Hapuku said the college had a zero-tolerance attitude towards drugs although this was hard to police.
But he said police and hospital staff had praised Fairfield for its response and management of the incident at the time.
"It was critical to know that our students and our staff were safe.
"We isolated these students very quickly as soon as the issue was identified."