How to change light schedule?

Hey guys,

I'm hoping there's an answer to this one. There's been heavy police helicopter activity in my area the last week or so and I'm slightly concerned that they might pick up on my house being hotter than everyone else's. Now I've done a lot of reading and have seen that it's not as easy as I first though I. E they can't see your lights through walls or your grow tent in your room etc but only the surface temperature of your property.

Having said this km concerned that they might notice a routine I. E 12 hours of hotter surface temperatures at night.

What I need to know is, is there anyway I can change the light schedule so my lights are on during the day and not the night time that they currently are. Currently they come on at 9pm and go off at 9am.

I only did this as my house is an "eco home" and is always so hot during the day that it got a bit too hot in there last grow however since I have upgraded all my ventilation.

I don't vent my hot filtered air outside just into the room. My plants only have around 4 weeks left. I thought perhaps I could gradually change the timers but would this cause them problems?

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That's totally shit for you!!!
Whatever way you choose will shock.

Your best option is to slowly decrease/ increse the timer by an hour a day until you get into your time you want.

All entirely depending on what stage you're at tho with the grow. (I'll assume flower as you stated 12 hours)

Second option is to go dark out for an extra 12 hours. You may see some sign of shock but if it keeps your mind at rest then it's worth it! There will be mixed feelings about this, but that's the one I would do if you're running out of time.


Option 3 is to heat your entire house up and keep it steady on the thermostat to that of your grow room. Low 20's if you can!

Thanks for the reply mate. I'm probably over reacting and I've tried to reason with myself. Firstly my block are all eco homes and are all insanely well insulated, walls roof triple glazed windows so it's unlikely that my grow tent is putting out much heat on the outside surface but I just can't help to worry!

Option 3 had crossed my mind and because it's out again tonight I've already adjusted the timers an hour in the hopes that they will be gone by the time it all heats up. The other idea I've had is to take my filter outside of the room and in to the hallway to disperse the hot air from the tent more evenly around my house. Really didn't want to plunge them into 24 hours darkness when they are looking like the best crop I've ever had by far. I should mention that I only have 2 600 watt lights and they are in the cool tube hoods so my 6 inch fan sucks all the hot air right from them to the outside of my tent through my carbon filter.

Any idea how much stress it would cause to plunge them into darkness for 24 hours? Am I at a high risk of them going hermie?especially being only 4 weeks off harvest?

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Thats not a big issue I had this problem before, changing the lights not helicopters. All you have to do is when it turns off at 9am don't turn it on until 9am the next day so now your on schedule again,one day of no light will not hurt the plant especially in flower ,however interrupting that 12 of darkness will really stress the plant.

You can always interrupt the daytime but never the 12hrs of darkness!

kali kid greenthumb said:

Thats not a big issue I had this problem before, changing the lights not helicopters. All you have to do is when it turns off at 9am don't turn it on until 9am the next day so now your on schedule again,one day of no light will not hurt the plant especially in flower ,however interrupting that 12 of darkness will really stress the plant.

You can always interrupt the daytime but never the 12hrs of darkness!

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Hey, thanks for the reply. Not second guessing you but just want to make sure that it won't cause any problems them being dark for 24 hours? Obviously I know when they are asleep that it's vital to not interrupt them just wasn't sure that 24 hours of darkness would cause problems so late into flower?

Thanks again both you

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Im very sure like i said I've done it before with no signs of stress, the plus side is I didn't water that day because there was no light. For example people will turn off lights to foiler or any other light maintenance for hours sometimes the cannabis plant responds to long nights to flower not light. One day is not gonna do anything to the plant im very sure of that.

Awsome, one thing though I don't know if it would affect that (can't see why it would) but I am growing in hydro?

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Doesn't matter I would just suggest you cut the feed to one feed for that day because there is no light and thats it. If its a system where the roots are in the solution(dwc/aeroponics etc..)then just leave it as normal.

lambert99 said:

What I need to know is, is there anyway I can change the light schedule so my lights are on during the day and not the night time that they currently are. Currently they come on at 9pm and go off at 9am.

Click to expand...

If you're in 12/12 in flower, I would move your time forward:


In this manner you're creating a longer day through longer "off" durations. 12 on, 15 off.

That would be better than going backwards, which would give you a shorter day through shorter "off" durations. You don't want that because it could signal to your plants they should veg instead of flower.

The suggestion to do it abruptly (in one 24-hour off time) might be ok. But, I'd break it up a little as long as it moves forward, with the off duration being longer (the on duration remaining 18 ).

(If I were in veg I'd go backwards, shorter off duration.).

Don't think too much about it , just think of it as a one day power outage I'm sure this cannabis plant has been through worse situations then one day of darkness, if it was that sensitive to "one" day of total darkness I'm sure this would be a well known and documented subject. However you choose to do it just don't interrupt that 12 hrs of night as you already know!

Cool I can stop worrying a lot now. Was really starting to worry me especially as they are really looking great. By far the happiest looking plants I've ever had and I know it's hard to tell but man they look like they are going to yield some nice amounts! Now just have to manage the smell, it's the cheesiest smelling weed I've ever grown!

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