Or it could be salt build up. It could also be Pythium wilt too. Or just plan old over watering.

You are not feeding them at that age anyway so there should not be a salt build up unless your grow rocks were not sterile to start with.

More likely the last one.

Is there an odor from the roots?
Does the grow medium smell at all?
Zandor Reviewed by Zandor on . Can anyone tell me what is the problem with this SOS seedling? This sexy orange skunk seedling has developed dry brittle (like clay) leaftips; orangeish-green in color...any help/suggestions will be appreciated...lw blue areas indicate where all the leaf damage is...This is a shame, because these sexy orange skunk did not germinate well out of 5 3 grm'd, all died except this one...the first 2 might have been moth eaten, just like my clones :( :( :( ...and you are not gonna believe, I found this black/white spider jumping around my clone area awhile Rating: 5