can we have both open when we do the soil/water feature?
you cannot have the game in which you want to soil/water your pots actively running. the safest thing to do is to exit PT altogether. I have not tested it (someone please test it?), but it may also be possible to just switch to a different game in plant tycoon, do the soil/water thing in VST, then switch back to your game in plant tycoon.
the real danger is not the soil/water button. By the way, you do not and should not press SAVE after pressing SOIL/WATER. The Save button is to save your seed transfers.
So are there any real dangers? Only one. Having your active game running in plant tycoon, then in VST accidently moving seeds, and then pressing save. 100% of the time, that will cause a permanent loss of the virtual seed tray and all the seeds that were in it.
pressing the soil/water button theoretically cannot hurt anything. the worst that should be able to happen if you forget to switch to another game or exit plant tycoon, is that the pots won't get soil/watered.
so far no one has lost any seeds to my knowledge. but sooner or later someone will accidently do the one thing that will automatically invalidate the virtual tray and all the seeds in it. So to repeat, this is what you want to avoid doing: have the active game running, move seeds in VST, and then press save. That automatically invalidates the virtual tray and all the seeds in it. Don't do that. It is bad.