Most people don't choose reincarnation. Reincarnation finds their way to them. Perhaps they did something great in their life. Or maybe truck-sama wasn't looking where it was going. But without fail, those who reincarnate are destined for something great. A new life where everything changes for the better. But... Reincarnation isn't always the greatest thing. Sometimes you just draw the short end of the stick. Di Tou just happens to have drawn the shortest stick. Pulled out of his life randomly. Taken by a crazy old eccentric man not as a disciple, but as a body double?! And a janitor body double no less?! Grasping a system to find... It's a JANITOR SYSTEM!? Truly, how unlucky can one get?
Thinking about it this way, everything seemed to make more sense to Di Tou. After all, the soil could be attributed to be like a medicine or poison. It had once been said that all medicine is poison, only that the benefits outweigh the consequences. Thinking about the long list of potential side effects that were listed every time a medicine ad came on television, Di Tou understood this principle rather deeply.
So, thinking from this perspective, the Fiery Dandelion seeds could simply be considered allergic to the Rich Soil, making it so that the negatives outweighed the positives and resulting in the seed's demise. But with the addition of [A Gentle Touch], it only endured the positive effects and thus was able to go through a metamorphosis, becoming this slightly larger seed instead of dying.
As for why it got larger… Di Tou had a very stupid theory that he thought might be true.