I use seaweed on a large scale, being able to get it here at $1.90 a ton, which is fairly cheap. The only problem is, it is very light on nutrients so it takes a LOT of it, about 10 to 1 in terms of PH. I can get Mill Lime for $22 a ton, but despite the difference in price, because I am not paying to moving 10 times more of it, Mill Lime is actually a better deal.
Another problem is how diluted it is. While it has some astounding properties, again it takes so much, that smothering on grass ground can be a problem. In other words, I can only apply so much and not kill the grass, so it is of limited use. Again, Mill Lime is a better deal. Of course where tillage takes place, that is not a problem because a farmer can dump on 10 tons to the
acre and just till it in.
On a home
gardening scale, I doubt a person could haul enough seaweed from the ocean and hurt their garden because it is so diluted on nutrients. However, it does have some micronutrients that are hard to get otherwise. It is good stuff, it just takes a lot of it!