smell-how far can it travel?

[Grey Bear]

The problem is not really how far it will travel.
The problem is how long will it linger.
On a breezy day the smell may be perceived much further away, but is much harder to localize.
On still days it may not travel far, but is very easy to find.
So outdoors you want to be sure your cover does not block normal prevailing winds.
Indoors, the ideal is to have adequate carbon filtering and to exhaust as high as it is reasonable to do.
Connecting to the hotwater tank vent is a great solution as any illegall FLIR use by LEO will only reveal an already warm exhaust.
And since the heat from the tank is already rising up the vent it will provide additional exhaust pull from your grow area.

 

[KapScot]

OBSUFICATION

In urban environments - some border planting can help. For example marigolds have a scent that is quite similar to Cannabis and could be used in plain sight to mask a secretive grow elsewhere that your neighbours might discover << this might be a factor for indoor growers as well as outdoor

http://www.ipm.iastate.edu/ipm/hortnews/1996/3-15-1996/mari.html

They are also a useful companion plant if you grow carrots or other root veg as they distract the carrot root fly thru the pungent odour of the marigold leaves. Just be careful where you plant them or your small secretive grow might start smelling like a huge skunk farm - it's all about plausible deniability. If you are doing an indoor grow then pots of marigolds could be the cause of the strange smell in the house (to the inexperienced grower). But if that's enough to keep the neighbours happy it's a result. Ive seen small growers give their neighbours small plants for their garden borders so that they acclimatize to having something that smells a bit like cannabis. Nasal Training.

 

[KapScot]

@Grey Bear - Quote "Indoors, the ideal is to have adequate carbon filtering and to exhaust as high as it is reasonable to do.
Connecting to the hotwater tank vent is a great solution as any illegall FLIR use by LEO will only reveal an already warm exhaust.
And since the heat from the tank is already rising up the vent it will provide additional exhaust pull from your grow area." End Quote << Sorry quotes seem to be broken for me.

There is another way too - one that is particularly useful in older properties. Here in the UK there are a large number of older properties which have 'real fires' - as in fireplaces. I live in a old circa 1905 Victorian building - each fireplace is serviced by its own chimney. And wooo I discovered a large chimney breast (above the small fireplace - like up the chimney).

Now I'm not allowed by the missus to do indoor grows but you can bet that's where you will my bud drying after harvest. The chimney constantly draws air (from the house so it's dry air) and last year I managed a smell free cure up the chimney so to speak. I know a lot of properties wont have such large spaces up the chimney - I have a 3' ledge up there so lots of room for criss crossing wire hangers, but an old real chimney that draws air should do so continuously and would provide a similar vent to your water heater vent idea with deniability on FLIR.