The Heart Foundation was also supporting it and a Toi Ohomai Institute of Technology culinary arts tutor did food safety with volunteers, she said.
"It's been so rewarding and we've had great feedback from schools."
She said they started at the beginning of Term Three and it was their pilot.
"We know from research that eating healthy food increases children's ability to learn and concentrate in class.
"Making sure they get a nourishing lunch will help them learn for the rest of the day."
She said some principals and teachers had mentioned it helped with attendance and class behaviour.
Ms Jackson said they were doing about 250 lunches a week and might do as many as 100 in a day depending on orders.
They had delivered to Whakarewarewa School, Rotorua Primary School, Te Kura Kaupapa Maori o Hurungaterangi and Te Whare Kura Ngati Rongomai. Next term they would like to take on another four schools.
"If anyone wants to contact us we are happy to hear from schools which are interested."
Ms Jackson said Ka Pai Kai had some kick-start support from Healthy Families Rotorua, but the initiative was self-funding.
She said families paid between $1.50 to $4 for the lunches with the cost subsidised by sponsors and donations.
Ka Pai Kai Rotorua's summer menu includes a hidden vegetable lasagne and lunch bags with chicken salad sandwich, yoghurt, a homemade treat like frooze balls or mini muffin and fresh fruit. There is also a chicken and coleslaw option.
"We want the healthy food to be able to compete with the unhealthy food price-wise."
The Rotorua Energy Charitable Trust gave $10,800 to Ka Pai Kai Rotorua, as one of 19 grants approved in August.
The funding would help the organisation with set-up costs, including a 12-month kitchen lease.
She said they were grateful to all the people in community who had come forward to help in various ways or doing deliveries.
"We couldn't offer it without the support of volunteers who have come on board and we are grateful for all the input we've received."
Rotorua Primary School principal John Naera said they had found the lunches to be substantial, healthy and value for money - "it's been amazing".
Mr Naera said he saw pupils lining up for the lunches and it looked like the line had grown from about 10 when it first started to 45.
"The kids like them and feel they are getting good value for money."