When I wrote this post the reasoning was I planted a limpwurt seed instead of a white lilly seed, rookie move. That is when I discovered using your spade on the patch to try and remove the plant didn't work, which I guess is understandable to avoid the abuse of gaining exp rates through seed planting/digging up etc.
To me, it makes complete sense to have planting exp removed at the planting stage and rewarded at the final harvest or even when removing a dead plant because you still planted the seed so you shouldn't be completely at a loss. This way if you dig up a plant that isn't fully grown or dead then you don't receive anything, you're making that choice.
It allows us to correct our mistakes rather than having to wait for the plant to grow or die. None of this causes any disadvantage to new players, if they don't know they could compost seeds etc then they should read about the skill first. Also, the low level seeds are very low cost so I can't imagine players getting very upset over losing a few gp.