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★Mark us as a preferred sourceThe Honolulu organic waste program, known as G.R.O.W., is available across the whole island of Oʻahu from 1 October 2026: every household on the city’s three-cart collection system can now put kitchen food scraps into the green cart alongside yard waste. Meat, bones, rice, bread, eggshells, coffee grounds – everything that used to end up in the general trash. Below is a plain-language guide to how the Hawaiian system works, what can and cannot go in the cart, and what other cities – including those in Hungary – can learn from it.
In short: From 1 October 2026, the Honolulu organic waste program (G.R.O.W.) lets households on Oʻahu’s three-cart system put kitchen food scraps, including meat, bones, rice and coffee grounds, into the green cart. Taking part is free and the pickup day stays the same, but food must go into the cart loose, without a bag. The collected material is turned into certified organic compost.
What is G.R.O.W.?
The name is an acronym for Green Recycling Organic Waste. The programme was launched by the City and County of Honolulu’s Department of Environmental Services (ENV), and its slogan is simple: “Include the food.”
The rollout was gradual. On 1 April 2026 a pilot phase started in six communities: residents of Waipahu, Nānākuli, Hawaiʻi Kai, Mililani, Kailua and Kalihi were the first to add food scraps to their green carts. Building on that experience, the city extended the programme islandwide from 1 October, so every household using the city’s automated three-cart curbside collection can now take part.
Participation is voluntary, but the city strongly encourages residents to join.
Why kitchen scraps matter so much on an island
On an island, landfill space is an especially scarce resource. According to city figures, Oʻahu households generate roughly 60,000 tons of food scraps a year, while local media have reported up to 180,000 tons of food waste across the entire waste stream. A 2017 city waste characterisation study found that organic material made up around 36 percent of all discarded waste, and according to ENV, food waste alone accounts for roughly a fifth of the trash generated each year.
Until now, this material has typically gone to the H-POWER waste-to-energy plant or the Waimānalo Gulch landfill. Food decomposing in a landfill releases methane, one of the most potent greenhouse gases, and it takes up valuable space. Wet kitchen waste is not an ideal fuel for incineration either. Composting, by contrast, keeps food out of the landfill, cuts emissions and returns a nutrient-rich soil amendment to the land.
Honolulu’s messaging ties this to a local value, mālama ʻāina – caring for the land and the people around us.
How the Honolulu organic waste program works in practice
The key point is that residents don’t need a new cart and don’t pay an extra fee. They use their existing green cart, collection happens on the same day as before, and the green cart is still emptied every other week. Regular trash and mixed recycling collection stay unchanged.
Households follow just three steps:
- Place a kitchen container in a convenient spot.
- Collect food scraps and spoiled food in it.
- Empty the container into the green cart – loose, without a bag.
The city also provides a free kitchen pail or a reusable silicone bag, available at community workshops or from the ENV office. The launch was supported by presentations, workshops, videos and printable flyers – the latter available in ten languages besides English, including Hawaiian, Japanese, Korean, Tagalog, Samoan and Vietnamese, which is essential in such a diverse community.
What goes in the green cart – and what doesn’t
Jenn Boneza, Public Information Officer at ENV, sums up the rule in four words: “If it grows, it goes.” The official list is indeed generous, accepting far more than you would put in a home compost bin.
Accepted – food scraps and wasted food:
- fruits and vegetables, including peels and cores;
- dairy products that are solid or semi-solid at room temperature, such as cheese and yogurt;
- bread and baked goods;
- pasta, rice, grains and cereal;
- beans, nuts and seeds;
- meat, fish, seafood, poultry and bones;
- eggshells, nutshells and seafood shells;
- leftovers, spoiled food and plate scrapings;
- loose coffee grounds and tea leaves.
Accepted – green waste: grass clippings, leaves, branches, hedge trimmings, palm fronds and natural Christmas trees.
Not accepted: liquids, paper and paper products, plastic, metal, glass, fats, oils and grease, products labelled “compostable” or “biodegradable”, pet waste, coffee cups, takeout containers and pizza boxes, fast food wrappers and packaging, corks, rubber bands, produce stickers, twist ties, and dirt, rocks, bricks and plant pots.
The city also stresses that home composters should keep doing what they’re doing – and use the green cart for items that don’t belong in a home compost pile, such as meat, bones, dairy and cooked grains.
Odours, flies and tropical heat: practical tips
In Hawaiʻi’s climate, fortnightly collection and food scraps don’t sound like an ideal match. For many residents the first hurdle is what Jenn Boneza calls the “yuck factor”, so the city offers simple, practical advice.
Its number one tip is to keep food scraps in a bag or container in the fridge or freezer until the night before green cart pickup. Then empty them into the cart loose, without the bag. This stops scraps from breaking down in the heat and keeps the cart cleaner.
The other key to avoiding odours is layering. Bury food scraps under yard waste, leaves and grass clippings so they don’t stick to the cart walls and attract fewer flies. Sprinkling baking soda over scraps also helps, and the cart is best kept in the shade.
What happens to the collected material?
The contents of the green carts are taken to the Hawaiian Earth Recycling composting facility near Wahiawā. The company was selected through a public request for proposals and made a significant investment to prepare for processing. The end product of industrial composting is a certified organic soil amendment used in gardens, agriculture and city parks.
Residents outside the three-cart system can still take part: food scraps can be dropped off at the composting facility free of charge, with a limit of two self-drop-off loads per day.
Why even “compostable” bags are banned
It may seem odd at first that the programme excludes bags and containers labelled compostable or biodegradable. According to the city, plastic contaminates the whole batch, and at the facility a “compostable” product cannot be told apart from conventional plastic at a glance. From a technical perspective there is another reason too: such products often take longer to break down than a facility’s composting cycle, so partially degraded fragments can end up in the finished compost. The cleanest solution is for food to go into the cart loose, with no packaging at all.
The same logic explains why meat and bones are accepted. In a home compost bin they cause odours and attract pests, but at an industrial facility, with higher temperatures and professional management, they can be processed safely.
Lessons for Hungary and Europe
Under the EU Waste Framework Directive, since 2024 every member state must ensure separate collection of biowaste or its composting at source. In Hungary, however, many municipalities still accept only garden waste in the brown or green bin, while kitchen scraps – especially meat and bones – are excluded. Local rules vary from place to place, so it is always worth checking with your own waste service provider.
Honolulu’s example offers a few simple lessons:
- Pilot first, then scale up. The six-community trial made it possible to fix problems before the system went islandwide.
- A clear message. The “Include the food” slogan and a short, illustrated list are easy for everyone to understand.
- Convenience at no extra cost. Same cart, same day, no extra fee – which dramatically lowers the barrier to entry.
- A free kitchen container. A small thing, but habit change starts in the kitchen.
- Information that reaches everyone. Without multilingual materials and community workshops, even the best system fails on contaminated carts.
The most important lesson, however, is that the best waste is the waste never created. Honolulu’s own guidance starts with shopping and cooking mindfully – the green cart is only for the scraps we truly can’t use.
FAQ: Honolulu organic waste program
What is the Honolulu organic waste program?
The Honolulu organic waste program, known as G.R.O.W., is an initiative of the City and County of Honolulu’s Department of Environmental Services. It lets households put kitchen food scraps into the green cart alongside yard waste. It started as a pilot in six communities in April 2026 and was extended to all of Oʻahu from 1 October.
When can every household on Oʻahu take part?
From 1 October 2026, every household on the island that uses the city’s automated three-cart curbside collection can take part. Before that, from 1 April, only residents of Waipahu, Nānākuli, Hawaiʻi Kai, Mililani, Kailua and Kalihi could add food scraps to their green carts. Participation is voluntary, but the city actively encourages it.
What food scraps can go in the green cart?
Almost all solid kitchen scraps: fruit, vegetables, bread, pasta, rice, solid dairy, meat, fish, bones, eggshells, seafood shells, plate scrapings, coffee grounds and tea leaves. Liquids, fats and oils, paper, plastic, metal, glass, pet waste and packaging are not accepted. Food should be emptied into the cart loose, without any bag.
Why can’t compostable bags be used for collection?
Because plastic contaminates the whole batch, and at the facility a product labelled compostable cannot be told apart from conventional plastic at a glance. Such products also often take longer to break down than the composting cycle, so fragments can remain in the finished compost. That is why food scraps must always go into the green cart unpackaged.
Does taking part cost residents anything extra?
No. Residents use their existing green cart, collection happens on the same day as before, and there is no extra fee. The green cart is still emptied every other week. The city also provides a free kitchen pail or reusable silicone bag, which can be picked up at workshops or at the ENV office.
How can residents avoid odours in the green cart?
The city’s number one tip is to keep food scraps in a bag or container in the fridge or freezer until the night before pickup, then empty them into the cart loose, without the bag. Burying food under leaves and grass clippings keeps it off the cart walls, and baking soda and shady storage help too.
What happens to the collected food scraps?
The contents of the green carts go to the Hawaiian Earth Recycling facility near Wahiawā, where industrial composting turns them into a certified organic soil amendment. It is used in gardens, agriculture and city parks. Residents outside the three-cart system can drop off food scraps at the facility free of charge, up to two loads per day.
Can food scraps go in the brown bin in Hungary too?
It depends on the municipality. Since 2024 the EU Waste Framework Directive has required separate biowaste collection or composting at source, yet many Hungarian municipalities still accept only garden waste in the brown or green bin, excluding kitchen scraps – especially meat and bones. It is worth checking with your local waste service provider.
Sources:
- City and County of Honolulu, Department of Environmental Services – G.R.O.W. program
- G.R.O.W. informational materials: https://www.honolulu.gov/env/ref/grow/#Flyers
- KHON2 – Honolulu expands G.R.O.W. food recycling: https://www.khon2.com/living-808/honolulu-expands-grow-food-recycling/
