Speaking at the RHS Lindley Hall launch of the event last week, at which 60 million Britons are invited to have street parties to eat homegrown food, she said: "There is a danger communities will get even more fragmented in the times we're going through. Food and gardening are simple ways to unite people."
Blears said that with President Barack Obama's visit to London, there was a real sense of something stirring. "This is about knowing your neighbours," she said.
Eden Project chief executive Tim Smit said: "If we can't create communities that can work together, we're never going to have a future.
"The future is not about individual actions; it's about a fundamental way of changing the way we work and live. If no one comes, I'll be bothered because it tells us something about our future."
RHS chief executive Inga Grimsey said: "We can get people directly to nature through the garden. In troubled economic times, they're looking for values they've lost."
She added that "garden centres are running out of plants and seeds to sell" and that "community veg doctors" can encourage people to start growing vegetables for the first time.
- See www.thebiglunch.com.