Why are there always notification numbers on the app's icon in my phone?

In order to quickly remind you of your progress towards your daily water consumption goal, the app's icon shows a number in the upper right corner corresponding to the number of glasses you still need to drink to reach your daily consumption goal!

In the meanwhile, to comply with the Apple design guideline, Garden development team gas made a slight adjustment. Here is how it works now:

If Gardener has set any specific time to receive notification (e.g. 10:00 am) and you haven't finished your daily suggested drinking goal today, by 10. am you will see the notification pop out as well as the number of water you haven't finished shown on top of the icon.

However, once you click on and close the app (or just hit "home" button and return to the home page), the number will disappear and will show up again until the next reminder is set.