AsNoriuanswered grow question 6 months ago I grow in soil. So adding silica is against any logic even, but ...
When grew in mass was using Buddha Trea silica acid , forgot exact name. Dosage was 1 ml/L for foliage, 2ml/l as water/feeding additive . Was using during 2-3 waterings , i do plains, so it could be 20 days or 5 waterings duration. Was starting those feeds only after final stretch was over in flower , so 3-4th week of it.