Black on new growth? Is it a slimy type of stuff? Use a q-tip to see if it rubs or flakes off. If so, likely you've got mold.
Fish emulsion is a veg nute, not for flowering. (unless it's to correct a problem)
If your humidity is getting up to 86%...that's way too high. Would keep a fan on 'em.
A clear picture would be helpful.
Rusty Trichome Reviewed by Rusty Trichome on . Sick plants All of my plants have yellow spots on parts and more on others. One plant has lots of yellow spots on the leaves all over. New growth has black tips. There are also holes in some of the leaves that i thought were from mites. IDK though I hope this is enough, but ill will get pictures in a bit. S=Answer if you grow traditional soil E-indoor Rating: 5