The race is on to raise as much money as possible before popular Pilton beauty spot Mannings Pit goes up for auction at the end of March.
The 21-acre plot of land goes under the hammer at a sale run by auctioneers Clive Emson on Thursday, March 26.
The Friends of Mannings Pit have stepped up their campaign to buy the land and preserve it for the community.
They say the site has been used by generations of local people for walking and leisure and they want to prevent any development on there.
The land is listed for sale with a guide price of £225,000 to £275,000 and so far the community appeal has raised £51,492.
The auction listing for the site describes it as land 'east of Windsor Road', rather than the name Mannings Pit, under which it was designated an asset of community value.
That rating only means the community be given an opportunity to buy it if it comes on the market.
The Friends group launched its campaign in 2015 when the site was bought at auction and subsequently Summix (Barnstaple) Ltd lodged a planning application for 138 new homes, later revised down to 41 and then withdrawn in 2018.
Friends chairman Christine Lovelock said: "Let us hope some developer isn't misled (as the present owners were when they bought it in 2015) into thinking they are just buying 'some fields'.
"They only need to look at the council's planning files, or our history of the planning application to see that buying Manning's Pit in the hope of building on it is not a good idea.
"We don't know how much more money we can raise in just three weeks.
"This part of North Devon isn't a wealthy area, but we are giving it our best try. So please spread the word far and wide, and donate if you can."
The campaign has received a boost after a donation from David Wilson Homes, part of Barratt Homes, which is building the new residential development adjoining Manning's Pit.
Friends treasurer Tim Saunders added: "People need homes, but they also need green spaces.
"We have never been against development where it is needed - and in the right place. That place is not Manning's Pit."
The Clive Emson auction is taking place at St Mellion in Cornwall on March 26 and will feature a range of properties.