Sweet bottanical herb

Vermicompost is natures' ideal plant food and if pure, can not burn plants. Your plants are suffering a lack of trace elements which can be solved by adding volcanic rock dust to your substrate, but at this late stage and with a need to act soon, a dose or two of soluble trace element mix, available from any garden centre, will help your plants greatly, with the leaves returning to a normal colour/condition within a few days. True nutrient lock out does not occur until the substrate is below 5.5pH or above 7.5pH, both highly unlikely situations, with no real lock out occurring anywhere between 5.8 and 7.4. Enzymes are good for the substrate and will not burn your plant either, unless given in ultra high concentrations or amounts. Hope this helps, Organoman.