The scientist said Northland should also add value to milk products, for example, by creating an Omega 3-rich Manuka honey ice-cream.
"We missed the Greek yoghurt boat. What happened?"
She also said the recent trend of Asian companies setting up food production companies here to ship produce back to Asian made no sense.
The outspoken professor was also not impressed with regional councils' approach to environmental policy to regulate farming.
"The polices tend to be ahead of science." She said regional councils needed to work more closely with farmers.
"Regional councils should talk to top farmers to see what they are doing so it can be applied elsewhere. Farmers know their own land and think holistically."
Councils were "beating up" agri-businesses and preventing "the people who can fix the problem from coming in", as farmers did not want to be seen as "anything other than stars".
Rowarth urged Northland farmers to question available science and request that decisions made on-farm be based in solid, good science.
She also criticised Steven Joyce's Budget 2015 announcement to create three regional research institutes to be based outside of the major urban centres.
Instead, she said, they were making grand announcements about new funds and new centres, while removing support from existing facilities, such as Niwa and AgResearch.