I tought it was a temperature problem so i bought an heat mat and put it under the pot, but the problem seem to be only worsening considerably and i got no clue on the matter.
I think it's a pH correlated deficency of some kind since it's 6.1 but i read that above 6 it's fine for soil, so before acting i'd like to have some recommandations from you guys.
Thanks as always.