No disagreement there.
I would add that plant based nutrition is far superior to synthetic/commercial types of supplements. The body assimilates them much better and the liver doesn't need to work extra hard.
Added to kelp I would throw in dulse and add grasses such as barley. Again the important thing to realize as 108 suggested is that the soil is key. it must contain a wide array of minerals and also soil organisms to get those minerals into the roots of the plants.