The "bumper crop of rocks" thing almost certainly started as one of the show's jokes - it's one of the perennial (literally, as in every year at planting time) things you'll hear anyone with so much as an herb garden say as long as its in the actual ground rather than a window box or something, and the origin of those oh-so-scenic stone walls around traditional fields. A new crop of rocks comes up every spring without fail.
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"Anko, what you do in your free time is your own choice. Use it wisely. And if you do not use it wisely, make sure you thoroughly enjoy whatever unwise thing you are doing." - HymnOfRagnorok as Orochimaru at SpaceBattles
woot Med. Eng., verb, 1st & 3rd pers. prsnt. sg. know, knows
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"Anko, what you do in your free time is your own choice. Use it wisely. And if you do not use it wisely, make sure you thoroughly enjoy whatever unwise thing you are doing." - HymnOfRagnorok as Orochimaru at SpaceBattles
woot Med. Eng., verb, 1st & 3rd pers. prsnt. sg. know, knows