Tomorrow's Harvest was promoted with a cryptic marketing campaign that began on Record Store Day 2013, with the release of an unannounced non-album single that featured part of an unidentified code.

"[5] During the recording sessions, Boards of Canada used a wide range of vintage hardware and equipment, including an effects unit "that cost [Eoin and Sandison] a lot of time and road miles to source."

Sandison described Tomorrow's Harvest's final track, "Semena Mertvykh" (translated from Russian "Семена мёртвых" — "Seeds of the Dead"), as having "a deliberate feeling of complete futility."

"[7] Andrew Burke points out thatThe album's dominant themes, environmental collapse and the degradation and decay of the landscape, fit closely with a strain of genre cinema from the 1970s and 1980s.

Most significant perhaps is a late 1970s Canadian film Deadly Harvest released on VHS, an eco-thriller about dwindling resources that features an eerie synth score by John Mills-Cockell.

Boards of Canada had previously hinted that it would be played there by tweeting satellite images[14] and uploading a video to YouTube featuring a distorted advertisement for the park titled "Look Sad Reel", an anagram of Lake Dolores.

[21] AllMusic reviewer Heather Phares said that although "the album doesn't reveal any dramatic changes; this is undeniably the work of Boards of Canada, filled with the melancholy melodies and subtly edgy rhythms", adding "it is as comforting as a collection of quietly menacing android fever dreams.

"[31] Writing for Consequence of Sound, Michael Roffman noted that the "seraphic ambiance of 1998's Music Has the Right to Children [...] reemerges weathered and with a newfound sense of purpose" and described Tomorrow's Harvest as "emotionally-stirring, calculated epic of ambient electronica".

"[24] The Independent reviewer Laurence Phelan noted that "there is joy in these grooves; the attentive care of studio perfectionists, and the warm embrace of an old friend" and that the album "is instantly and unmistakably identifiable as their own".

Rather than working around the edges of their sound in search of new territory, Tomorrow's Harvest finds them drawing back toward the center" and noted how "the creative energy [..] is directed toward building textures, which are very deep and rich indeed.

"[28] Sean McCarthy of PopMatters summarised that "though demanding repeated listens, Tomorrow's Harvest distinguishes itself by making intense commitment" and noted that the album "continues that tradition of complexity and accessibility" in his nine out of ten review.

[33] Spin's Andy Beta rated Tomorrow's Harvest nine out of ten and said that "the record draws more from cinema than contemporaneous electronic music", noting that it "captures Terrence Malick's magic-hour light; there's also David Lynch's sense of dread coursing beneath the mundane; the arpeggio-heavy synths that underpin early-'80s horror-movie soundtracks; the Hammer Films catalog; and The Wicker Man itself.