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You don't have to place the plants in pots. If you use the MoveObjects on cheat, you can just plant them inside a room with no floor. They'll still be dormant but you don't have to worry about the bulky planters and can do this with trees which can't go into the planters. Plus this way doesn't require any expansions at all.
There is a sticky under University Life about all of the Herbs. Herbs are added after a meal is cooked to give the same moodlet it would if you ate it raw. All of my research shows that eating it raw is better anyway because the moodlet lasts longer.