This is how I resolve searches for herbs.
One step I have already taken is to create a list of all herbs by climate/region. This way I quickly see what is available in the area. However, you can go through the list and note all available herbs in the area by climate for each search in a few minutes, with help from players.
So lets say the search is in a mixed forest, deciduous, with fresh water, short grass available. The players make their foraging roll (one roll with mods), and then I go down the list, adding the mod for dificulty to find. All herbs with a result of 111 or higher are found. I roll 2d10-the dificulty number, and that is the number of doses found. If the area is near civiliaztion, I only roll 1d10-#, or if it has been searched in the last four months/growing season.
lynn