Sorcerer Potion

Take a couple of poisonous skins (like snake fangs), mash them up, simmmer, add something suitably nasty and mystic (Vvrael blood?) that is probably bought from an alchemy shop for 5k but could be dropped by a critter, chant 705.

Each dose poured on the ground causes a lot of weeds and one useful plant to die, with the consequence of there being fewer forageables in the room but lower rolls needed to find them.