When the player presses the throw button while the leader is under an Onion's beam, the Onion menu will open. In general, this menu allows the player to specify how many Pikmin they want to have with their leader. Because of the Master Onion in Pikmin 3, this menu is radically different in that game.
If the player goes up when the number of Pikmin in the party is already 0, a "boing" sound effect will play, and a message will appear, warning the player about an invalid request. A message will also appear if the player goes down when there are 0 Pikmin in the Onion or if the limit of Pikmin on the field has been reached.
Pikmin and Pikmin 2
In Pikmin and Pikmin 2, the background of this menu is a simple box with the color of the Onion. It contains three boxes with numbers. The top one, accompanied by the symbol of an Onion, indicates the number of Pikmin of that type that are present inside the Onion. The bottom one, with a symbol of Olimar followed by Pikmin, indicates the number of Pikmin of that type that are currently following the leader – as such, this count ignores idle or busy Pikmin. The final number indicates the number of Pikmin in the exchange.
When the player tilts / , or presses / up or down (though only the Control Stick works in Pikmin for the GameCube), the numbers change: pressing up requests one more Pikmin to be stored in the Onion, and pressing down requests one more Pikmin to the group. By pressing the throw button, the player can confirm the exchange, and by pressing the whistle button, they can cancel it. Any Pikmin requested to be added to the party will come down from the Onion, and the Pikmin requested to be removed from it will climb inside.
In Pikmin 2, the Pikmin that appear alongside the leader symbol change as the number of Pikmin in the party increases or decreases.
The games keep track of how long the player has held up or down while inside the Onion menus. These values are used to determine how quickly to move the Pikmin counter in the specified direction. They increase with time as the player is holding the respective direction, and drop down to 0 when the player releases. In Pikmin, since these values are only updated while inside the Onion menus, and are shared between them without being reset, a player can hold a direction in one of these menus, confirm while still holding the direction, go towards a different Onion (free to do anything with the analog stick in this step), start holding the same direction as they enter the next Onion's menu, and the game will use the same counter speed as the previous menu did. For New Play Control! Pikmin, the same technique works, and works with as well, though the player has to stick to either the analog stick or the D-pad, since they are not interchangeable mid-trick. In Pikmin 2 and New Play Control! Pikmin 2, the speed is forced to zero whenever an Onion menu is opened, so this trick does not work.
In Pikmin 3, this menu has a button to cancel, a button to confirm, and two buttons for every type of Pikmin associated with the current Onion. The latter buttons appear above and below each Pikmin type icon, and are used to pick more or less of them. These buttons can be held down to speed up the increase or decrease. / / can also be used to highlight the cancel or confirm buttons, or a type of Pikmin. Tilting the stick up or down will do the same as if the "more" or "less" buttons are pressed. The throw button can also be used to confirm, and the whistle button to cancel, except under the stylus mode.
/ can be pressed in order to select all types at the same time. The "more" or "less" commands will then count for all Pikmin at the same time. If there are not enough Pikmin of a certain type in the party or in the Onion, the number will stop changing for that type, but will continue changing for the others.
A label at the bottom of the screen will also show how many Pikmin are in the field, in total. It is possible for the player to store Pikmin and call out different ones in a single go, instead of having to store the Pikmin, wait for them to go in, and then call the new ones out.