Device for determining the quantity of water required by a cultivation medium, and a plant tray adapted to implementing the device

A plant tray adapted to implement a device for determining the quantity of water required by a cultivation medium, said tray comprising a main compartment (21) for receiving the cultivation medium and plants to be cultivated, and an auxiliary compartment (22) separated from the main compartment (21) by a vertical partition (6;

• 106) whose bottom portion allows water to pass therethrough and which supports a measuring wheel (1;
• 10) disposed vertically in the auxiliary compartment (22), the measuring wheel being mounted on said vertical partition in such a manner as to be able to rotate freely about a horizontal axis while nevertheless having an unbalance, the bottom portion of the measuring wheel (1;
• 10) being situated a few millimeters from the bottom of the tank of the tray, the measuring wheel comprising a first portion (4;
• 14) that is relatively unhydrophilic and that has a mean relative density less than unity, and a second portion provided with hydrophilic means (3;
• 13) causing the unbalance of the wheel to vary as a function of the quantity of water retained in the hydrophilic means (3;
• 13), with the measuring wheel (1;
• 10) or the auxiliary compartment (22) including display means (5;
• 15) for displaying the angular position of the measuring wheel (1;
• 10).