I have gotten 4 essence and I have produced maybe 4 stacks of inferium from crops and then destroyed them by hand. I know that they don't drop with a 'soft harvest' but I have also tried using the Actually Additions farmer as well as doing it by hand.

Here is the config info on the server -
# Enable Fertilized Essence? [default: true]
B:fertilized_essence=true

# Percentage chance that a Resource Crop will drop a Fertilized Essence when harvested. [range: 0 ~ 100, default: 5]
I:fertilized_essence_chance=8

Inferium crops dont drop fertilizer, every other crop should though.

Cheers! Thanks for the info. I couldn't find this online. That explains it then because I started growing a few water crops and it must have dropped from that... But after that I just grew straight Inferium. Thanks for the quick response.

@BlakeBr0 How would you feel if I added some config options to the mod like FertilizedEssenceSpawnsFromInferium = false/true and FertilizedEssenceSpawnFromInferiumRate = 0-100 so that the server owner could decide how they want this to behave? I'm a 4th year computer science student about to graduate and I'm looking for a fun project.