I swear Emilya told me the opposite. I wait til I see a tap root. Then that end is down. I believed that diagram at the start of this post was wrong. But, and it’s a big butt here, I did have one root that kept reappearing above the top of soil. I keep pushing it deeper til it behaved. Another but coming at you, I have been growing apple seedlings the last month or so. It very well could have been an apple. My brain cells are calling the fat lady to warm up her vocal chords.