Before proceeding, try to simply click the 'sync harvest date' here: https://app.getgrowflow.com/Sync/Index
If that doesn't get you where you're going, please read on:
When you transferred in inventory, we can't automatically look up the harvest date since you don't have access to the plant that the inventory came from.
No worries though, you can update the harvest date by clicking on the inventory detail button and then manually setting the harvest date.
If you set this on the parent lot, it will then get updated on all the children inventory and also passed down to new child inventory so you only need to set it once!