Harvesting Kelp/Seaweed for Potassium Fertilizer

[Easy]

Hello friends. I'm in need of fertilizer for my mango trees. I'm withholding nitrogen for the most part (to help keep them compact), so I'm focusing on phosphorus, potassium, and secondary and micronutrients. I've read/heard that kelp/seaweed is great for potassium, and, wouldn't you know it, I live about 15 miles from the beach (S. Florida). My question is, can I just grab a bunch of kelp from the beach, hose it off, and mulch my trees with it for my potassium fertilizer? Thanks,
David

[Daintree]

I have tried this when I lived in Oregon.
First, check local regulations. You may need a permit.
Second, kelp stinks as it breaks down. Not sure, but I think most ofnthe benefit occurs after breaking down, so you have to put up with it. You can bury it lightly to prevent hordes of flying insects.
I found it more trouble than it was worth, and just bought seaweed fertilzer in the end.
But lots of folks do it, so can't hurt to try. Hopefully the tree isn't too close to a house window...

Carolyn

[Finca La Isla]

We spread seaweed under our trees sometimes and it breaks down alright. It can certainly be composted and microorganisms should help with any odor problem. I think it’s a good idea and it’s likely you can get a lot more minerals besides the potassium that you expect.
Peter

[Daintree]

Yes, there are a zillion micronutrients in it!

[vall]

The seaweed that typically washes up in FL is sargassum. Sargassum accumulates arsenic so no, not really something you want in your soil.

[Greater Good]

https://edis.ifas.ufl.edu/publication/FE1128

Check out this link.

[SanDiegoCherimoya]

I've harvested kelp and soaked it to goo in 55 gallon barrels here in San Diego. It stinks like hell, a lot of work, but the trees loved it.

[Easy]

Thanks all. Appreciate the link, GG. Perhaps I'll shoot an email to the city, see if I can't unburden them of some sweet, sweet compost. Living in S. Florida, ought my soil be sufficient in phosphorus already, or will I need to supplement that as well? I suppose a soil test may be in order, anyone know of such a service in S. Florida? Thanks

[Easy]

So, apparently the city of Ft. Lauderdale has a program where the seaweed is taken to Snyder Park and composted, tons of it. I'm thinking a ride down to Snyder Park is in order, see if I can't get a couple trash bags worth. I'll report back if it's up for grabs to the local public.