“Earth provides enough for every man’s need. but not every man’s greed” (or “Earth provides enough for everyone’s need. but not everyone’s greed”) has been frequently credited to Mahatma Gandhi (1869-1958) since at least 1959, but it’s not known when or if he said it. Protestant Christian evangelist Frank Buchman (1878=1961) said on his 69th birthday in June 1938:
 
“A friend of mine says; ‘There is enough for everyone’s need, but not enough for everyone’s greed.’”
 
Buchman’s friend’s name is not known, but it is known that Buchman helped to popularize the saying in the 1930s.
 
 
Wikipedia: Frank Buchman
Franklin Nathaniel Daniel Buchman (June 4, 1878 – August 7, 1961), best known as Dr. or Rev. Frank Buchman, was a Protestant Christian evangelist who founded the Oxford Group (known as Moral Re-Armament from 1938 until 2001, and as Initiatives of Change since then). He was decorated by the French and German governments for his contributions to Franco-German reconciliation after World War II.
 
Wikiquote: Talk:Mahatma Gandhi
Unsourced quotes
Earth provides enough to satisfy every man’s need, but not any man’s greed.
 
Google Books
Moral Rearmament:
The Battle for Peace
Edited by Henry Wilfred Austin
London: William Heinemann, Limited
1938
Pg. 63:
There is enough in the world for everyone’s need, but not enough for everyone’s greed.
 
5 June 1938, Springfield (MA) Sunday Union and Republican, “Buchman Speaks With U,S. Friends on 60th Birthday,” pg. 10A, col. 8:
“A friend of mine says; ‘There is enough for everyone’s need, but not enough for everyone’s greed.’”
(Protestant Christian evangelist Frank Buchman—ed.)
 
12 June 1939, Riverside (CA) Daily Press, “Flag Day in 1939” (editorial), pg. 16, col. 1:
As has been well said: “There is not enough in the world for every man’s greed but there is enough for every man’s need.”
 
HathiTrust Digital Library
The Psychology of Social Movements
By Hadley Cantril
New York, NY: J. Wiley
1941
Pg. 160:
Buchman is famous for his slogans and for his twisting of popular phrases.
(...)
There is enough in the world for everyone’s need, but not for everyone’s greed
 
Google Books
Enigmas of History
By Hugh Ross Williamson
London: H. Joseph
1957
Pg. 43:
There is enough in the world for everyone’s need but not enough for everyone’s greed.’ This principle, enunciated by Dr. Buchman from the outset of his work, is and always has been the economic creed of the Oxford Group.
 
Google Books
Towards New Horizons
By Pyarelal.
Ahmedabad: Navajivan Pub. House
1959
Pg. 12:
“Earth provides enough to satisfy every man’s need but not for every man’s greed,” said Gandhiji.
 
Google Books
The Survival Greenhouse:
An eco-system approach to home food production
By James B. DeKorne
El Rito, NM: Walden Foundation
1975
Pg. 5:
Ghandi was criticizing the capitalist system as much as stating a basic ecological principle when he said: “Nature provides enough for every man’s need, but not enough for every man’s greed.”
   
Google Books
The Sociology of Freedom
By Krishna Chaitanya
New Delhi: Manohar
1978
Pg. IX:
An answer suitable to every nation comes from Gandhi when he said, “there is enough for everyone’s need, but not enough for everyone’s greed”.