“Tidy house. tidy mind” is a popular saying, though not always an accurate one. “A tidy house is the symbol of a tidy mind” was cited in print in 1986.
 
A similar saying is “If a cluttered desk is a sign of a cluttered mind, of what, then, is an empty desk a sign?” “A cluttered up desk is the sign of a cluttered up mind” was cited in print in 1947.
 
“Tidy desk, tidy mind” has been cited in print since about 1948 and “Tidy room, tidy mind” since 1982.
     
 
Google Books
Potboilers:
Three Black Comedies
By Charles Marowitz
New York, NY: M. Boyars: Distributed in the U.S. by Kampmann
1986
Pg. 180:
And the Colonel is always gassin’ on about neatness in the home, and how a tidy house is the symbol of a tidy mind.
 
OCLC WorldCat record
‘Tidy house, tidy mind’: contesting the boundaries of self-determination and acceptable risk in PDRS clients’ management of ‘home’
Author: Carter, Meg
Publisher: Psychiatric Disability Services of Victoria (VICSERV) 2008
Edition/Format:   Downloadable archival material : English
 
The Independent (UK)
Thrifty living: Why does saving money end up costing so much?
BY ROSIE MILLARD   SATURDAY 29 MARCH 2008
(...)
Is it better to keep, or to chuck? A tidy house equals a tidy mind, and thus (hopefully) a tidy set of accounts, but if you have thrown everything you have ever worn away, you will be left with no clothes whatsoever, meaning an urgent credit-card-exercising trip to H&M.
 
The Independent (UK)
Old adage ‘tidy house, tidy mind’ is true claims new survey
RELAXNEWS   MONDAY 07 FEBRUARY 2011
The results of a survey released on February 3 suggest that the saying ‘tidy house, tidy mind’ could be true, with the majority of respondents in the United States feeling stressed or anxious about the amount of clutter in their houses.
 
The survey conducted across the country by Russell Research on behalf of online personal organizing site Rubbermaid found that 91 percent of respondents are “overwhelmed” by the untidiness of their house, 57 percent say a disorderly house is a cause of stress, 42 percent say it makes them feel more anxious and slightly under half of all respondents claim they “won’t invite friends over” to see their home when they feel it is “cluttered.”