River Cottage star Fearnley-Whittingstall formed the scheme at the height of the grow your own boom, when allotment waiting lists reached 150,000 and the credit crunch recession was peaking.
Staff at the site have moved on to website Crowdfunder.co.uk, which asks the public to back social enterprise projects.
Allotment waiting lists fell from 57 people waiting per 100 plots to 52 per 100 plots between 2011 and 2013, after which campaigners stopped collating statistics.
Some 22,000 people signed up to Landshare within weeks of its launch on Channel Four to offer spare land to frustrated gardeners, but the scheme has lost momentum, with it last Facebook post before the announcement of its closure being almost two years ago.
Croatian garden fan Danijel Balaban posted on the Landshare Facebook site this week: "Too bad to see such a great project go offline. I've emailed three times about starting one in my country to which I never got a response."
Landshare said: "Sadly, after seven years, we’ve decided to close the Landshare website.
"Launched on Channel 4 in 2009, the website tapped into the big surge in interest in grow-your-own and a shortage of allotments.
"Since then more than 75,000 people have signed up to food campaigner Hugh Fearnley-Whittingstall’s scheme, which was first unveiled on Channel 4 during River Cottage’s ‘Summer's Here’ series.
"We’re extremely proud of our achievements, but we’re afraid it’s the end of the road.
"The website hasn’t been supported for some time and it’s beginning to show. Unfortunately there’s nobody waiting in the wings to take over so we’ve arrived at this difficult decision.
"But it’s been a wonderful journey, and we’ve achieved some amazing things.
"We will be closing the website on Wednesday 24 February, giving everyone a fortnight to grab what they need before it goes for good.
"The core team behind Landshare and River Cottage's other campaigns, such as Chicken Out and Hugh's Fish Fight, are currently working on Crowdfunder.co.uk, the fastest growing crowdfunding platform in the UK.
"Hundreds of new community projects are added daily, with thousands of exciting new ideas turned into reality each year."
The scheme's Facebook page remains live.