This study investigated the effects of input flood tasks, as focused tasks, and Jigsaw tasks, as unfocused tasks, on promoting Iranian English as Foreign Language (EFL) learners' recognition of regular past tense /-ed/ in terms of accuracy and durability. Accordingly, using a quasi-experimental study, two intact university classes including 62 participants were randomly designated to experimental and comparison groups. The participants were homogenized regarding their language and grammar proficiency levels. The experimental group was instructed through input flood tasks and the comparison group through Jigsaw tasks. Analysis of covariance (ANCOVA) analysis showed that although both groups' mean accuracy scores were improved on the immediate posttest, the experimental group outscored the comparison group. However, the results of the delayed posttest demonstrated that whereas the comparison group maintained their accuracy level over time, the experimental group's accuracy mean score dropped. It can be postulated that input flood tasks may promote learners' recognition accuracy of second language forms immediately, but this effect may gradually diminish. Hence, it can be tentatively concluded that Jigsaw tasks result in more durable gains than input flood tasks. The findings imply that when the goal of grammar instruction is to achieve durable effects, unfocused tasks should be integrated with focused tasks in the syllabus.