Tumblers help turn around rodent issues at Tatuanui School

| By Ruairi Kelly, Enviroschools Waikato and Tatuanui School

The bin arrives and is set up.

Enviroschools is an overarching culture of Tatuanui School in rural Waikato, woven into whole school life including the strategic plan.  The school values reflect this in Caring, Attitude, Responsible, Enviro-kid – we care!

It started with a problem: rodents were nesting in the school recycling area. After exploring alternatives, they decided a grant (fund administered by Waikato Regional Council for Enviroschools within the region) would help them finance compost and wormery equipment they had investigated and decided would help keep rodents out.

They worked along-side their Enviroschools facilitator Ruairi, using the Action Learning Cycle to ensure they were meeting the criteria. The fund application was successful! !! Students ordered two tumblers and two Hungry Bin worm farms.

When the equipment arrived, the tamariki were excited to get stuck in and took the lead. The seniors did a great job of putting the compost tumbler and worm farm bins together.


Using the Action Learning Cycle to guide inquiry and action.


Designing a healthy worm habitat.

Students mapped out the area and considered what needed to be incorporated in good design.









As part of “we care” duties, one group does worms, one does compost. They have built an understanding ratio of greens and browns, wet and dry. They had an idea to do comparison with the systems, but life happened. The tumbler worm population was more temperamental than the old bath system so there were a few problems with attrition. They had kept the old baths though. The old system can cope with a greater amount of tissues and the worms love it. This means less paper shredding.

 “After the worms have eaten all the nutrients and made the poop…it helps grow and replace nutrients Supersonic soil going back on gardens.” – Kyle, student

Worm cafes serving up the best in Tatuanui.

The compost tumbler system.








They considered the pros and cons of the 2 systems:

  • the tumblers are good for small operations and good for dealing with non-seedy weeds.
  • given the size of the school grounds, to get a supply of ‘supersonic soil” they calculated that they would need 5 tumblers.
  • they have learnt to keep separately: because of hygiene a teacher does the tissues. The students do the greens. They have also learnt not to do the mixing on a windy day!
  • good compost needs more time in the bins and the tumbler requires less brute strength (although there would need to be systems around this with multiple bins).


“We have compost bin at home on the farm with way more worms. I prefer the tumbler as we dump it and the worms do their thing…turn 5 times and the worms eat it.” Eleanore, student

Adding compost to the garden.

Distributing the compost around the vegetable gardens.








Trial and error were part of the learning. Students observed the tumblers weren’t in direct sunlight and knew natural heat was important for assisting and accelerating natural decomposition. One of the tumblers has since been moved into a position where it receives full sunlight to test the differences in compost breakdown speed.

“We have 130 students who pack in pack out. Food scrabs go to tiger bins but we have a job balancing too much /too little. We have a push mower to get extra greens into the tumbler and everybody gets involved in mowing the bits the grounds person can’t get to. The students have also been able to self-manage with combination of pack in/ out.” –  Rob Haddock, lead Enviroschools teacher, Tatuanui School

Covid and winter ills hit hard. When eventually teachers and students were back it on-site, activities needed to be postponed and adapted. Tuākana-tēina groupings had to be changed and social distancing had to be considered. Because of absence of students and leaders, projects took longer and keeping student engagement and the impetus proved difficult. Rodent trapping, previously a regular undertaking, went on the nice to do list rather than need to do from all other elements of school life.

Future evaluation will include recording the amount of brown (carbon) vs green (nitrogen) waste going into the compost tumbler to perfect the recipe over time.

Students and teachers alike are impressed by the difference compost makes to the school’s raised gardens.

The compost area is really helpful as it decomposes tissues and grass from our field to make the supersonic soil. The SS helps plants grow more than normal soil. – Kyle, student


We take it over to front gardens in containers to help the plants grow with nutrients.” – Eleanore

To target the rodent pest problem, traps were installed nearby and regularly checked. No pests have been caught since the tumblers were installed, which suggests the unwanted visits by rodents has been addressed. To test this theory though, students plan to add detection devices like ink tunnels and chew cards to monitor presence/absence. This will hopefully offer further reassurance that the better-contained food scraps in the tumblers and worm bins are no longer attracting pests.

Still on the plans to do predator work and Enviroschools Facilitator, Ruairi will assist with this and connect the schools with Predator Free Waikato.