by putting dry seaweed
through an electric compost shredder.
Chipped like this, seaweed breaks down far faster:
The additive of choice for all tomato plants!
It makes sense to collect dry seaweed from above the tideline:
as seaweed is typically 5/6 water by weight,
a shoulder-load of dry weed
gives a much better return on effort.
Tip: avoid kelp stalks –
your machine won’t like them.