When you have reached Level 8, you will be able to unlock them Well Garden Expansion with the Small Well. The Small Well needs to be restored before it can be used so choose a Farmhand that will help with the task.
Once it has been restored, you can now collect water from the Small Well every 2 hours. The Small Well will accumulate up to 5 Water before it’s full.
Water can be used to speed up crop growth.
You can also purchase additional Wells from the Building Shop which unlock at higher levels.