Caro Hart, development manager for sustainability charity Projects in Partnership, said the launch of grownupgreen.org would definitely go ahead, but if £50,000 isn't secured by the end of November, the site will have to close at Christmas.
The charity spent £50,793 in the last financial year setting up Grownupgreen, and needs about £94,000 a year to continue.
The idea for Grownupgreen came up two years ago when Projects in Partnership couldn't find a website providing practical information to households wanting to live a greener life. "Our target audience is what Defra calls the 'would-be-greens'," said Hart.
The site will cover issues ranging from the use of chip fat as fuel for cars, to self-build housing co-operatives. It aims to be interactive, with users getting vouchers in return for sending in stories.
Hart suggested that the site was hampered by its own innovation, because funders tend to back a safe bet.
"I think we have a unique product," she said. "Where is the venture capital in the charity world?"
Also, despite appearing to fit neatly into government priorities, the site doesn't fit the restrictive criteria of grant-making bodies. "We've researched government sources, but we're not 'social' enough for the Home Office," said Hart. "We're not 'waste' enough for the Landfill Tax, and we're not 'regeneration' enough for Defra."
EU funding is available mostly for job creation or regeneration projects, and many of the 60 or 70 trusts that were approached wanted to fund larger charities.
The cash reserves that Projects in Partnership had saved also worked against it, as grant makers only make awards once funds drop down to two or three months of running costs.