"Summer's Cauldron" is an extension of an original poem Partridge wrote called "Drowning in Summer's Cauldron". It is introduced with the sound of a bee that pans across the stereo channels. Rundgren provided the sample, along with other "summer sounds" such as crickets and barking dogs. The track emphasizes droning sounds and a "wobbly" chorused organ, the latter of which reminded Partridge of summer and the Beatles' "Blue Jay Way" (1967). Rundgren played melodica, Partridge recalled, "and "we" got to bully "him"! It was "great"." Prairie Prince was encouraged to play "spastic" drum fills in the style of Jethro Tull's "Sweet Dream" (1969). "Summer's Cauldron" segues seamlessly into the next track, an effect that was achieved in an unconventional manner. "When we said, 'How are we going to get from 'Summer's Cauldron' to 'Grass'?,' he said, 'Well, you just put your hand on your instruments and stop the strings ringing and then we punch in the start of 'Grass.'"