According to director James H. Kay on the evening when the scene of Joe Dallesandro swimming nude in the pool was filmed half of San Juan showed up on the location to watch the shoot. Kay says apparently someone leaked the news that a nude scene was going to be shot that evening.
Recording sound for the film was extremely problematic because the filming locations were inhabited by hordes of tree frogs whose croaking was quite loud.
Director James H. Kay wanted the film to be entitled 'The Gardener' and only went along with re-naming it 'Seeds of Evil' at the insistence of the distributors who thought it would be more marketable under that title.
According to director James H. Kay, at one point the people who owned the house the film was being shot at wanted to evict the production from their property when shooting was only half complete. The production brought in lawyers to work out a deal, but while this was going on director Kay prepared to quickly return the crew to the house and not leave until filming was complete. Fortunately, the lawyers came through and the crew was allowed to continue shooting at the location.
The film's investors played the guests at the Bennett's costume ball.