It should not normally be necessary to reset your Controller. If you discover that your Gro Controller has become unresponsive, you may first try simply power cycling the unit. Be sure to wait more than 30 seconds before plugging the unit back in again. If the controller has overheated, you may need to wait till it has returned to room temperature by letting it cool down in your house, unplugged.
If that does not seem to bring the device back online, you may need to reset the Gro Controller.
Finding the Reset Pin
The small hole with the reset button is between the power plug and the zone wire terminals, underneath the Gro unit.
You will need a paper clip or pen to insert into the hole to access the button.
Keeping the Gro Controller plugged into your power outlet, insert a paper clip in the hole and press and hold for 15 seconds and then release.
The Gro Indicator will momentarily turn pink. Then the unit should cycle through colors while resetting and then return to a solid green indicator. From this point, though you will not need to create a new account, you will pair the device is if it were new. In the Gro app and tap the Settings gear > Reconnect Controller. You may also have to reset your Wi-Fi pairing if you were using Wi-Fi.