Grass seed had been sprayed on the 1000sq m "natural play-scape".
Teacher and playground development co-project planner Geoff Markby (pictured) said the only plastic element of the playground would be a plastic access slide.
"We really wanted to create something that would really give them [the children] an opportunity to engage with nature."
The $85,000 project would include sand and water features and a problem-solving area where pupils could create their own obstacle course, Mr Markby said.
There would also be totara, rata and kowhai sections.
He expected the playground would open in late October after a three-year effort.