For when you're on the bench. ;)

[TimberWolf]

According to this handy online calculator, a 12 foot by 8 foot room will need about 4800 watts of lighting for optimal growing conditions.

The gas discharge lamps that site seems to recommend are around 15% efficient, so the energy wasted generating heat will be around 4000 watts. That's about the same as keeping granny warm with a four-bar electric fire, so nowhere near enough to attract the attention of a thermal imaging helicopter in a respectable residential area.

50 watts per square metre doesn't sound a great deal for fast growing plants. According to this source the UK receives about 4 kWh per square metre solar insolation a day, in summer. So about 150 watts/m^2 constantly over 24 hours, for comparison. So your 50 watts/m^2 (which I assume is on 24 hours a day) is a third that provided by a British summer sun. All things being equal (which they may not be).

But yes, if it is 4 kW I concede that might well sneak under the radar and keep the guy upstairs happy too.

[NickFitz]

50 watts per square metre doesn't sound a great deal for fast growing plants.

I wouldn't have a clue myself, but given that the site with the calculator sells the lights it's unlikely their calculator is going to underestimate - unless they were stoned when they implemented it, which is a distinct possibility

[NickFitz]

Very interesting but how would you deal with the distinctive smell (hypothetically, of course )?

When my neighbours were growing plants in the ground floor rear, they tried a plug-in air freshener in the hall. All this meant was that as you came through the back door, the pungent aroma of skunk that filled the back yard became an even more pungent aroma of skunk with faint undertones of summer freshness

[Sysman]

According to this handy online calculator, a 12 foot by 8 foot room will need about 4800 watts of lighting for optimal growing conditions.

The gas discharge lamps that site seems to recommend are around 15% efficient, so the energy wasted generating heat will be around 4000 watts. That's about the same as keeping granny warm with a four-bar electric fire, so nowhere near enough to attract the attention of a thermal imaging helicopter in a respectable residential area.

A Dutch mate tells me they look at your leccy bills.

Or more often, your neighbours' leccy bills (cos lots of people steal it from neighbours).

Mind you, in the UK they've probably got the added problem of working out who your leccy supplier is and working out how much they are overcharging you.

[Freamon]

According to this handy online calculator, a 12 foot by 8 foot room will need about 4800 watts of lighting for optimal growing conditions.

The gas discharge lamps that site seems to recommend are around 15% efficient, so the energy wasted generating heat will be around 4000 watts. That's about the same as keeping granny warm with a four-bar electric fire, so nowhere near enough to attract the attention of a thermal imaging helicopter in a respectable residential area.

Sounds like you've done a lot of research and covered all your bases.

[Alf W]

The bin men could snitch you up as well when they notice your wheelie bin is half full of jaffa cake wrappers.

[xoggoth]

Magic mushrooms look much easier and more economic:

Growing magic mushrooms on Drugs-plaza