Almost said dirt tasted gud.
But because she said tasty,
Rain wrote the wrong number of syllables while being hasty.
(In the strip in question, the last line of the haiku originally read "because it is tasty", as shown in the January 25 News entry from the front page:
Special thanks to my sister, who wrote the haiku in today's strip.
EDIT: As my sister, and several others, pointed out, by changing the word "good" in her original haiku to "tasty," which I just think is a funny word, I made the final line six syllables, rather than five. I totally meant to change "it is" to "it's," to compensate, but I forgot, which is what happens when you work too close to deadlines. (That's today's moral, kids.)
I've fixed it, because, as an internet cartoonist, one of the perks I get is I can be as much of a revisionist as I like. Now, let's think about other things besides inaccurate syllable groupings in haikus about eating dirt.