Find the planting schedule you want to duplicate and click on the three vertical dots next to the crop in the "My Crops" list, then click "Add succession":
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The planting schedule will be duplicated and added as a succession planting schedule based on the succession spacing listed when adding or editing the crop planting schedule.

In this example, we are adding a succession planting of lettuce with two weeks set as the default time between succession spacings (so the new planting is entered two weeks after the original one).
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You can repeat this as many times as you would like to create or duplicate planting schedules in the calendar.
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