This is an interesting video on JADAM and feeding your garden with seawater:
I have to admit, the JADAM style of farming is quite “out there,” but it is always thought provoking. With the high dilution rates it is hard to see how this would work, but they are getting good results.
Personally, I would be tempted to dilute seawater more like one would dilute urine to use as a fertilizer, perhaps 6-10 parts fresh water to one part seawater, then water with it every few weeks.
This video also made me wonder if seawater might be a good anti-fungal agent in the garden. Some experimentation is definitely in order.