Garden Design for soil health with Vetiver clumps

This is the vegetable garden layout/design we are experimenting with.

We actually mix up the food plants rather than block plant, but they are mainly annuals of different market garden types. 

  • No need for paths because Vetiver mulch protects the soil and stamping down is a regenerative agriculture principle. (So long as it isn't heavy traffic).
  • My distancing is based on Indian research in regard to clay pot irrigation. While a Vetiver clump is not as gravitationally dynamic (clay pots water rate is spread horizontally through the forces of gravity), the ability of soil to hold and permeate moisture is the key principle.
  • With the soil covered with mulch, a Vetiver clump should moisten in an arc around itself depending on the atmosphere, groundwater volume, age and depth of the established Vetiver plant, and the microclimate impact of the surrounding Vetiver clumps & mulch.
  • A single, established Vetiver clump would offer its own accumulated microbiological web community and carbon fill much more so than: (a) a newly planted slip, and (b) a hedge of Vetiver located at some distance from the individual food plant. Distance, I see as the problem with hedges surrounding plots.
  • While you'd trim the clumps down to 30 cm and use the trimmings as mulch, clumps laid out like this would sabotage the use of machinery and may make team harvesting more difficult. However, established clumps are less likely to die if they are over-run by rambling plants like tomatoes, climbers, squashes, gourds, beans and the like. So there is that structural, trellising, element.
  • Any irrigation method would primarily be deployed to sustain the Vetiver circuit and to keep moisture flow pathways open because moisture begets moisture.
  • I suspect that 'shallow' and light irrigation as required, may do this better and more efficiently than pouring lots of water into or onto the bed. Testing or judging moisture levels in the centre of each block of Vetiver clumps before watering would make sense.
  • While not a hedge, staggered Vetiver clumps like this will still serve as wind breaks and can be grown to height according to how relentless the sun may be on the food plants around each clump.
  • I spent 10 years exploring clay pot irrigation methods here in the hot Australian sub tropics on sandy soil and in my schematic mind, I'm replacing each 'pot' of water with a living Vetiver plant while looking for BETTER results.
  • Anecdotally I can say that using Vetiver this way -- and growing a green mulch as required -- ensures that the bed requires less irrigation input -- less water effort -- than the clay pot irrigation system. That's' pretty good when clay pot irrigation (along with wiking beds) are the most efficient irrigation systems in terms of water usage.
  • So if you can keep your Vetiver alive and verdant you can grow the foods partnered around it as an intentional symbiosis.
  • If I am wrong, and the clumps need to be closer to one another, then the layout won't work because working among the clumps would be difficult and food plant growing space would be reduced too much.
 I've used rows around growing beds and it is, I guess, the norm. But I thought that if you don't need the hedge as a defence against erosion or to consolidate terraces, then you can be much more pragmatic. 
I also faced the problem that many food plants were asked to grow at some distance from the Vetiver so I was missing out on the supposed advantage of the Vetiver partnership. You can deploy narrow bed strips between Vetiver hedges, and I've seen a lot of that being done, but that would mean that you dedicate so much of your growing space to Vetiver. Probably unnecessarily and with the disadvantage that the hedge rows get in the way of management. So why not seek a happy medium for the companionship? 
IF your criteria is irrigation then you have a distancing principle, because I'm assuming a Vetiver influenced soil arc of around 70 -90 cm radius. I don't know of any research that has studied this issue quantitatively but if Vetiver is an hydraulic pump, even a weak one, then the principles that underlay the use of clay pot irrigation can be applied. Of course, maybe a hedge is much more dynamic than a single I have to see how this setup pans out over time.
Here's how it looks like in my experimental patch  :