The Root Control Discs (RCD's) are designed to fit both the 8.5L and 15 Litre pots that go into the 1-Pot system, the easy2grow Kit & the 2-Pot extension trays.
These discs are black & gold in color and are placed in the bottom of the pot, gold face down.
The purpose of the Root Control Disc is to prevent roots from leaving the pot & heading towards the AQUAvalve. They are very effective due to the special copper coating.
Please note that roots have the ability to go through concrete, therefore it is wise to occasionally lift the pot to see if any have managed to escape the barrier. If so you can simply cut away the roots with a pair of scissors. This will in no way harm the plant. We recommend replacing the discs after each crop as this will prevent any disease from being transferred from one crop to the next.