"Depends on the magic" John replied. "Depends on what you're doing, how you're doing it, experience" he shrugged casually as he worked. He briefly let go of the pestle, taking a drag on the cigarette. He blew some of the smoke into the mashed mixture and stubbed out the cigarette in a nearby ashtray. Picking up the pestle, he started working again.
He picked up the vial of blood and tapped it a few times before uncorking it and adding the liquid. As he did, he muttered in old Norse, under his breath. "Blood of the Master, cursed by rebirth, I John Constantine, turn your own blood against you, poison it with these wild things three. Nightshade, garlic, bloodgrass" He added the blood droplet at a time until all of the blood had been added. The mage placed the vial aside and took a moment to compose himself. He rolled his shoulders and reached for the next item. Next he added the soil, and he started working on mixing and mashing everything together.