Wyndham frequently acknowledged the influence of H. G. Wells' The War of the Worlds on The Day of the Triffids.
In regard to the triffids' creation, some editions of the novel make brief mention of the theories of the Soviet agronomist and would-be biologist Trofim Lysenko, eventually thoroughly debunked. "In the days when information was still exchanged Russia had reported some successes. Later, however, a cleavage of methods and views had caused biology there, under a man called Lysenko, to take a different course" (Chapter 2). Lysenkoism at the time of the novel's creation was still being defended by some prominent international Stalinists.