Were Babylon's Hanging Gardens just a Vertical Farm?

Took the offspring to the British Museum's "Babylon" exhibition - not a resounding success, most of it is as dry as Babylonian desert to kids who wanted to see more of the city's walls, wars, whores and so on. One thing they did latch on to was the Hanging Gardens - why were they built? The "official" explanation is that King Nebuchadnezzar built them for his wife who was pining for her mountainous homeland. Huh! sniffed No 1 (teenage) sprog, in a paraphrase of Monty Python "using public money just to amuse some royal babe is no system for building municipal infrastructure".

Ah, the naivete of youth - where do they get such scepticism from

This of course got me thinking about TED, and Dickson Despommier's talk about Vertical Gardens as solutions for our cities today (more on this here). Big takeaways from this idea is that:

- Vertical Gardens increase effective acreage and incoming solar radiation by going up and spreading out a bit
- They are extremely efficient consumers of scarce resources like water, and you can target minerals to the plants rather than sowing them onto stony and fertile soil
- You can operate them year round

That set me thinking anew - the Babylonians in all other respects seemed most rational. What if they actually did do it for sound municipal reasons. After all, another part of the exhibition was about its 3 concentric walls, massive gates, moat etc - and another showed the city enclosed was none too big. This was a city built for sieges, and in sieges you (i) get a lot of hungry mouths pouring in for protection and they (ii) will sit on what land you may use in the city to grow food normally, and (iii) by and large besiegers will cut your access to outside food off.

Or, imagine your loyal populace take a dislike to you and start revolting? The King owning the Means of Production of Food in desperate times, and having it safe in his citadel looks quite smart. If it amused the Queen, bonus! Given that the moat was the Euphrates, water was not a problem - or rather, if the besiegers dammed the river and drained the moat (as the Persians eventually did) then medium term food supply is not the most urgent problem.

So, was the first implementation of Vertical Farming some 2,500 years ago?. I googled Google to see if anyone else had my brainwave - turns out that no, I am -as far as Google is concerned anyway - the only person who has hypothesised that The Hanging Gardens of Babylon were not in fact built for a Queen (or her ransom) but were a very rational approach to creating and controlling food supply in an urban ecosystem. Feel free to award me an Honorary PhD in Archaeology at any time......

As to Internet Tech content - not much, but you can get your plants to talk to you via Twitter. The Babylonians probably used slaves, which, if current calculations about energy usage of avatars vs Brazilian peasants are anything to go by, were more clean-tech