Potion of Healing (DMG, page 187):
You regain hit points when you drink this potion.Potions (DMG, page 139): Drinking or administering a potion to another character requires an action.
As answered here, it is possible to administer a potion to a creature as an action, even if it is unconscious. This makes sense to me, because drinking/administering a potion just takes some time. But that's not an inherent feature of the potion of healing itself, because it just says "when you drink this potion", not "as an action you can drink this potion".
Goodberry on the other hand states that a creature has to use its action to eat one of the berries.
Am I correct to assume, that one such berry cannot be administered to an unconscious creature? Because the unconscious creature cannot take an action, and administering the berry seems impossible.
Best Answer
By RAW, you may not be able to administer a goodberry - by RAI, you most certainly can
A very strict RAW reading would conclude that in order to gain the benefit of a goodberry, the consuming character must be able to use their action to consume it. However, as it happens, this question has been asked of Jeremy Crawford via twitter (whose tweets were, at the time, considered official rules clarification) and he responded thus:
So Jeremy would appear to believe that you should be able to administer a goodberry to an unconscious ally, just as you can administer a potion - and there's definitely nothing about that interpretation which is inconsistent with the other game rules or the fiction. In reality, you can induce a swallowing reflex by massaging the throat, which is helpful for feeding something to an unconscious person (or an uncooperative pet, as per personal experience) - that seems like a reasonable thing to be able to do with an action.