@jeremyb616, I've always counted "Day 1" as the day that the shell is off, and seedling leaves open.
I've seen many other growers do this too; I thought it was common practice.
Should "Day 1" be the instant the seed touches water for germination?
That seems almost the same as if a human child should be called 1 day old, the day of insemination; "Day 1" is the day the child is born (seed hatches from shell).
This diary has a detailed representation of what I do (but with using a Jiffy Puck, instead of planting seed directly in soil):
growdiaries.com/diaries/68030-fastbuds-strawberry-pie-auto-grow-journal-by-basementganja
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