Sorry but I didn’t mention killing crabgrass in the segment. The way they chopped and edited that segment was awful though so I can understand the confusion.  I did talk about an organic lawn weed killer called Weed Beater Fe which will kill leafy lawn weeds and not the grass but it won’t kill crabgrass since it is also a grass.  The only natural crabgrass control is Corn Gluten but it needs to be applied before the crabgrass sprouts and it prevents the seeds from sprouting…too late for that to work now.  Sorry for the confusion.