My plants have been on 12/12 for 3 weeks, I've got them coming on at 10pm and off at 10am. Anyway came home today at 2.30pm to find the light still on. Timer had failed. Switched them off straight away and they've been off for 5 hours. Question is what do I do now? Should I leave them off for the full 12 hours (meaning I'll have to turn them off at 2.30am) and try to work the schedule back to 10pm/10am over the next few days? Also, will the extended light period do any harm or will they be ok?