worm castings arent harsh at all, thats great shit(pun intended)or is it worm puke?lol, they will help eventually. what did you do? water them in or make a tea out of it? and clones respond well to worm castings in the soil, it isnt like it is a hard chemical fert. once i move clones to the cup i add about 25% worm stuff to the soil and have never had one burn. be patient and water that stuff in.