the assholes use FLIR (forward looking infrared radar) to pick out the unique wavelength of light that cannabis sativa reflects. the feds cannot filter out a single plant from the background reflections, but can detect a patch that is approx. 25' by 25'. therefore, grow single plants in many different locations in as direct sunlight as possible. stay away from evergreen trees...they (as someone said earlier) soak up water like crazy and the make the soil too acidic for C. sativa. try to avoid walking around your plants! if you trample the soil around them, they can be seen from the air as big bullseyes! that is the DEA's favorite method of detecting. i recently moved to the city from waaay out in the country where i had been growing pot for ten years, so now my garden is in the attic!