This study examined the effects of online procedural scaffolds (in the form of generic question-stems with context-specific examples) and the timing of scaffolding provision (immediate versus delayed) on supporting the online student question-generation learning process in a science class. A total of 78 fifth-grade Taiwanese students participated in eight online question-generation sessions. An online learning system equipped with a customizable scaffolding design in terms of content and timing of access was used. The results of ANOVAs on the students' week-by-week question-generation performance showed the immediate positive effects of immediate procedural scaffolding. However, the delayed procedural scaffolds group did not statistically distinguish themselves from the no-scaffolds group in any of the eight question-generation performances, nor did the delayed approach engender productive failure, as postulated by some researchers. The significance of this study is discussed, along with suggestions for related instructional implementations, online systems and future research.