I have been using it for quite 3 years now in the volunteer tree planting group "We Plant Oaks" on Facebook. The biggest problem with this system is that for a oak tree seedling (a very small tree of 8 months) that has not yet formed a sufficient root system, the amount of moisture from the dropper that is poured from the inverted bottle in which you will screw the plunger is VERY small. For a medium-sized pot, you should place 2-3 of these plungers adjusted and buried next to the plant's root to be sure. Health is not easily lost and the water from the bottle does not empty quickly as someone wrote above. On the contrary, an existing problem is that these "mustaches" made of cotton at the edge of each plunger start to rot after 2-3 months of use in contact with the new soil. It is a problem that can be solved by users since someone can place small cut strips of half a centimeter thickness inside the cross hole at the top of the plunger made of cotton or cotton thread. I would not choose them again. In their place, I would choose the watering cones made of water-permeable ceramic material, which are quite cheap. They cost 1.5 Euros and they have them at the plant stores on Eiripidou Street in the center of Athens.