The Muto Herbam Guidelines are as follows (ArM5 p. 137) :
Level 3: Change a plant or item made from plant products. Level 4: Change a plant or item made from plant products into metal or stone (Terram requisite). Awaken the consciousness of a plant (Mentem requisite). Level 5: Change a plant to bend or twist rapidly in place.
The level 4 guideline about awakening speaks of a plant, not of items made from plant products, as do the other base 3 and base 4 guidelines.
Suppose I would like to awaken the wooden door of my Sanctum. It is allowed according to these guidelines ? If yes, is it a base 4 spell, or one magnitude higher ?
A door is not a plant, it is a plant product. THe guideline refers to alive vegetables, not wood. Now, if youy have a door that is a living plant, yes, you can rise its consciuosness. My magus has an ivy as the door to his sanctum, so I can see that happening rather easily.
I believe your door, assuming it is quite dead, simply does not have anything that can be Muto'ed into awareness, so you should be looking at Creo Mentem instead, or perhaps Creo Herbam(Mentem).
Ok, so you can't awake an item made of plant products because... well there's nothing left to be awaken, the plant being dead
The idea was to use the Sanctum door as a Intrusion Detection System while the Maga is away.
Apart from replacing the door by a living vegetable, like an ivy as suggested by Xavi (and I must say I quite like that idea), any thoughts on how to magically enhance that wooden door of mine ?
I should add that my Maga is specialized in Intellego, Muto, Mentem, Herbam and Imaginem.
Intelligo Corpus, Base 5 : sense a specific piece of information about a body, like whether it is you who is opening it. If it is not, it can then be used to trigger whatever other effect you feel like putting inside. Creo Mentem to warn you, Creo Imaginem to make some noise, ... The only drawback is that you have to lower your Magic Resistance for the door to recognize you.
Intelligo Mentem can work too, but it will be Base 15.
Alternatively, you can make an effect that triggers whenever the door opens, with another triggered specifically by you (and whoever you want to put on the list of authorized people, see Rulebook p.99) suppressing it, but that requires Rego Vim, not your specialty.
Or, requiring only a lesser enchanted device, arrange for a purely mundane intrusion device triggered when the door opened (pots and pans and a rope works, or something similar). All of it out of sight inside the sanctum. Then invest in the door an effect (Rego Herbam, maybe Muto Herbam if you are creative) that prevents the intrusion device from triggering (by bending the door, maybe), and make sure it is restricted to you and maybe your apprentice(s).
Rego is usually the "combat" sort of effect. Movement, striking - that's Rego. But it doesn't have to be huge...
The basic is to have ReHe constant (Concentration) that keeps the door in place - shut or open, as the mage leaves it. Not overly strong, but strong enough. (And making an absurdly thick (size +1) door can make it both too heavy to move* manually and too deep to easily chop through - but see MuHe for that solution.)
(* Wood weighs about 3/4 ton/cubic yard (a cubic pace of water weighs 1 metric ton, and wood floats, so...). That's ~7 tons for a +1 "door" that's 1 pace thick, 3 paces high and 3 paces wide. Without Rego, it's goin' nowhere. )
If ReHe is high enough, any dead wood can strike out - anyone who's been hit in the face by a heavy door that opens too quickly knows that can be very real.
I also like to have a heavy beam on the back of the door - by default it drops into place, no way to open it mundanely. A secret knock/whatever lifts the bar up, the door can open - simple, less than Level 10, 1 vis, and impossible to force short of chopping down the door itself. (This isn't enchanting the door itself, but a smaller separate item - or enchant the door to Range:Touch and "any beam" could work.)
You could Muto the door into something soft, almost liquid for a moment, and trap someone's hand in it - but again, that would need Rego to both make sure it "surrounds" the hand, and to keep it from melting onto the floor. And/or muto it into metal(-like) so it can't be chopped down. Maybe something with complexity, to create a "stocks" to trap their hands?
Imagonem has some options - make the door appear to be a wall, and/or make it appear 5 paces to one side and let them chop at the stone wall for while. Or just create something scary - run, ya bastids! Or make a nearby window look like a hallway. Fly, ya bastids!
My personal favorite cheap defense (Level 4 item, 1 vis) against mundanes is a large (size +1) MuTe stone slab placed in front of a door or in a hall. Once/day, it changes to liquid momentarily, whenever someone steps near the middle of it. Sploosh go the feet, up to the shin, and then back to stone - not goin' anywhere except without their feet. Even if your mage is away for days, they have to figure out how to get out in the moment of sunrise/sunset, or they're trapped another 12 hours. You could do something similar with a block of wood on the floor (just hope they can't reach an axe).
Mentem? All day long. Scare them away, guilt them into leaving, knock them unconscious, make them turn themselves in to the guard - your imagination (and Lab Total) is the limit.
Now, if youy have a door that is a living plant, yes, you can rise its consciuosness. My magus has an ivy as the door to his sanctum, so I can see that happening rather easily.
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