This isn't a problem, I just don't understand and it's probably been explained somewhere but I can't find it.
When several plants need one drop of water playing one game gives perhaps 4 or 5 drops which is enough to fully water them all , but when I have only the one seed/sprout and it needs 2 drops of water I have to play 2 games. In fact for that dahlia I had to play 3 games, as immediately after being fully watered it went back to needing one drop. 
Playing a game makes a little rain. You can water all your plants with half a drop. You can't collect rain water and give more to a single plant -> use the watering can instead. And from time to time, the ground dries again. It was by accident, that it happend directly after you watered your plant. (It probably happens at specific periods.)
Maybe someone can tell more about drying hours.
When it rains, it rains evenly on your whole garden (just like in life). Doesn't matter which plant needs more or if you have one plant or a whole garden full, the rain comes on the whole garden equally. When you use your watering can, you have to fill it up as you use it because each plant takes a certain amount from the can, which holds a limited amount. So 5 full drops (10 waterings) from one game, because that's one watering can full. So if you think of it as each drop being an inch of water, in the watering can you have 5 inches of water (but collected in one narrow space). In the rain, the whole garden gets one-half inch of water each rain. More water total than the watering can, but you can't control where it goes.
