Supermarket Sainsbury's is to sell more than 500 of its own-brand products in compostable packs instead of plastic as it seeks to cut packaging waste.
Ready meals are next on Sainsbury's green-packaging agenda
It says the scheme, already trialled on some of its organic range, will save 3,550 tonnes of plastic a year.
Almost half its organic fruit and vegetables will be in the new packaging this week, and 80% by January.
Sainsbury's wants rivals to follow its lead, and is urging the government to provide compost bins for homes.
Ready meals will also come in the compostable packaging by January next year.
"We're now confident that putting 500 types of our food, from ready meals to organics, in compostable packaging will significantly help to reduce the packaging that most threatens the environment," said Sainsbury's chief executive Justin King.
"It also creates an opportunity for customers to dispose of their own waste at home."
The move is the latest attempt by UK supermarkets to improve their green credentials.
Tesco has launched a campaign, backed with adverts featuring Alan Titchmarsh, Ronnie Corbett and Paul Daniels, to encourage its customers to use fewer plastic bags.
Environmental campaigners Friends of the Earth welcomed the move - but said supermarkets had much more work to do.
"We hope Sainsbury's goes further and phases out all non-recyclable packaging," resource campaigner, Dr Michael Warhurst said.
"The supermarket chain must also take urgent action to reduce the impact that its operations have on the environment and farming communities.
"Today's announcement is a step in the right direction, but it has a long way to go before it can be viewed as a green grocer."
The group says that local shops and markets are often more environmentally sound as they often source local produce and sell fresh goods without unnecessary packaging.