minimumDate property
final
The minimum selectable date that the picker can settle on.
When non-null, the user can still scroll the picker to DateTimes earlier than minimumDate, but the onDateTimeChanged will not be called on these DateTimes. Once let go, the picker will scroll back to minimumDate.
In CupertinoDatePickerMode.time mode, a time becomes unselectable if the DateTime produced by combining that particular time and the date part of initialDateTime is earlier than minimumDate. So typically minimumDate needs to be set to a DateTime that is on the same date as initialDateTime.
Defaults to null. When set to null, the picker does not impose a limit on the earliest DateTime the user can select.
Implementation
final DateTime? minimumDate;