heat signature

Discussion in 'Growing Marijuana Outdoors' started by growgoat27, May 6, 2006.

  1. does anyone know about the heat signature of the plants? any information would be great. like how the swine detect it with the ray guns or whatever. how much is detectable in an outdoor grow in the woods? would any city have it installed in the birds?

    oh yea, i dont live in canada so american info would be good.
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  2. The whole story about marijuana giving off a specific heat-signature detectable by special cameras is a myth. It's a splicing of two aerial detection methods: using IR cameras to detect suspicious heat signatures in barns and houses (from the lights) and flying around looking for big patches of it in fields (it's pretty easily distinguishable from the air when you have 100 plants in the middle of a corn field) Both of these methods are used almost exclusively for major factory grow operations. You can't effectively spot "a couple" of plants from the air, not to mention the expenses that law enforcement agencies accrue by flying aircraft around all day (making it a rare occurence). I wouldn't worry about a few plants in the woods. I WOULD worry about an acre of pot in a field. :smoke:
  3. I agree with homebrewer , there is a lot of nonsense spouted about ´heat signatures´.

    IR detection devices are used to identify objects that are warmer than their surroundings. Warm areas in buildings, vehicles (hot engines) and people, we have all seen the police pursuit videos where the fleeing villains are glowing white.

    MJ, like any other plant, is at the same temperature as the air around it, and as such has no identifiable ´heat signature´. Grows are detected by visual spotting from the air, using the Mk. 1 eyeball. This can only be done in daylight.
  4. actually, it's just kind of a myth. The part that is untrue is that MJ some how gives off a special heat that is detectible. That's not how it works.

    It's not the heat of the plant that's being detected, it's the relectivity/refractivity of a plant. By using special cameras (one of them IR), one can pick out MJ among other plants do to the amount of light spectrum and heat the plant reflects.
  5. Is this why people say to intersperse with tomatoes? Do they have the same general reflect/refractivity? Also, any idea how sensitive they are? Could you pick out a plant or two in the woods? BTW, thanks for the info. I've had this debate a million times and never heard this concise information. What you're saying makes a lot of sense, logically.

    And yes, it IS wrong to whack it to pot pictures! LMAO :D
  6. I go for that, sounds correct science to me.
  7. thanks everyone that is a relief off my shoulders
  8. yup. tomatoes give off a similar, but NOT identical, heat/light reflection index (or whatever the hell it's called - it's been a while). If you had a large area of tomatoes with pot in between them all, it would make it harder, but hardly impossible to detect.

    This way of detection is how a lot of your rural living growers get busted planting 50 plants in woods behind their house.

    What confuses people, I think, was the use of FLIR (forward-looking infra-red) to detect heat off of actual grow ops (indoor). The amount of heat generated by the lights, pumps, nutrient tank heaters, ventilation, etc... was obvious in a FLIR scan and, in the past, was used as a basis for pulling utility records and securing warrants.

    In the United States, this is no-longer acceptible to obtain a warrant. The Supreme Court rules the IR scan as an invasion of privacy, but more importantly, an illegal search when warrantless.

    Does this mean that cops won't FLIR your house? FUCK NO! They will still do it. BUt they can't use that info to get a warrant or solely use that against you criminally. But they can scan your house and then confirm their own suspicions and have more reason to snoop around and watch your ass. Also, under certain conditions, they can get a "sneak and peak" warrant and then the FLIR scan is allowed.
  9. Just so glad I live in liberal Spain.
  10. Can IR detection pick up two 48" flourescent lights and a puny fan? Would that even raise suspicion?
  11. It is a total myth and I can prove it now. I got a plant stress meter this last year, which is basically just an IR thermometer. In other words it measures the plants heat signature and temperature. Cannabis does not give off a unique signature as far as I can tell. It read the same as my tomatoes, peppers, and all the other annuals in my garden.
  12. Blaze21 that sounds interesting. If you get a chance can you tell me what the readings are of pine and cedar trees compared to cannabis. They are supposed to be very similar. You say your annuals were the same as the cannabis, how about perennials? Thanks-
  13. Good question! I do not have pine or cedar where I am at - just oak.

    I just walked outside and took a few readings of my oak trees in the yard - they read between 4 and 5 degrees above ambient, which is hot. From what I was seeing last year, my cannabis plants and my annuals when they were not stressed usually read about 2 degrees below ambient temperature.

    I had not thought of this before - all my plants are mixed in with my veggies, so that was what I compared them to. I forgot that many people do not grow this way and often hide them in trees.

    I'll have to do some more tests though to get a more solid answer. It is 5 PM now and stress readings are best taken in the middle of the day. Also, it is possible that the three trees I just tested are stressed out and may not be a good sample. I'll have to take a walk around the woods this week and test some more oaks to get a better idea of what their average temp usually is.
  14. Blaze21- others, I just read some interesting info last night on this topic. The theory was, though cannabis may have a heat signature resembling other plants, when the budding starts they absorb heat during the day and hold the heat in the bud. Supposedly indicas hold heat better than sativas, due to the bud density. So while a plant vegging would not show up, a flowering plant would. Like anything with this topic, I'm not sure of its validity. but it does sound like a possibility.
  15. no any normal house could run 2 of those lights and they dont give of much heat anyways

  16. Hell yeah bro....I mean you could easily supply the south eastern united states with the amount of weed you could grow with two 48" tubes and a puny fan. They prolly already assembled the swat team. I'd start running for the hills if i was you. :D
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  17. Hmmm... I suppose that is possible. I know for sure though that during early and mid flower they do not read any hotter, at least during the day. I'll try to get a reading of some at the end of flower next time I get the chance and see if it is any different.

    Honestly though I have never seen a verified case of people getting busted for the IR signature of the plants themselves. There have been cases of people getting busted from the heat signature of lights however. There's a BIG difference between picking up on the heat signature of multiple 1k watt bulbs and a plant though.

    I am pretty skeptical about such claims of IR being used for outdoor though. I can tell you for a fact that here in CA, CAMP does not use any sort of IR sensing device - they do it all visually. Considering they are one of the largest marijuana eradication organizations in the country I would thing that if anyone was using such technology they would be.

    Rumors tend to get pretty blown out of proportion with these sort of things though. For example the county I am in bought a pair of small, remote drones to bust pot gardens this last year. They were very cheap, simple, basic models, that were small enough to carry in a backpack and have a VERY limited range and field of view. Of course once the rumor mill got a hold of it, suddenly everyone was claiming we have armed predator drones flying around, ready to launch cruise missiles into unsuspecting gardens at a moments notice (no exaggeration I've heard this from a lot of people this year). Where the heck is a county with 80,000 people going to get the funds to buy two multi-billion dollar top of the line military drones that require an entire team of specialists and a military air base to keep it maintained? It is pure BS of course, but still a lot of people believe it now...
  18. I think there is some good information on this page here Grow Marijuana FAQ, Cannabis cultivation - marijuana growing tips & photos. Although I'm not really sure whether heat is a real problem if the setup is in a basement.

    So my question is this. Would someone have to really worry about heat signature from a single 400W system properly ventilated (my exhaust actually vents inside my garage :cool:) with an average room grow room temp of 75 degrees?
  19. So putting one of mine outside in my fenced in back yard would be okay? There's no other foliage or anything. That's all I'm worried about. It will just be this one plant. Also the police station is pretty close by so the helicopter thing worries me a bit. On the other hand it's ONE PLANT. I wouldn't think they'd be able to see it. Even if they did I'm not sure if they'd even bother with it.

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