sir with due respect,,,correct me if i am wrong,,,since practice mo is direct method in sowing,i think no need hardening na, kasi your seedlings is already acclimatized to the system, and the root system is no longer disturbed since no transplanting of seedling conducted and there's no disturbance on the root system, which is the purpose of hardening, conditioning the newly transplanted seedlings to the nutsol and later to the grow boxes, for their growth ( vegetative - harvesting) period....