Re: Iodine and gardening

I don't know what you mean by kelp water
I go down the beach and get a car load of seaweed when I can, but an alternative is to get a liquid seaweed extract(with no chemicals of course) such as SM3 in the UK and spray the plants with it, that can correct a lot of potential deficiencies besides iodine, or just add it to a watering can, but that's more wasteful. Unless your adding piles of seaweed or spraying the leaves I don't think it's going to add much Iodine to the plants
and adding Iodine to the soil seems wasteful. Likely most will just wash out depending on your soil and amount of rainfall. Maybe potassium Iodide could be sprayed on the leaves without burning but not lugols.
It seems better just to take it yourself