Soil Building Part 2 – Seaweed brew

Chooks and worms do the bulk of my soil building, but compost can only contain the micronutrients of the ingredients that go into it. Using some ingredients from trees that deep mine subsoil, and some weeds that are dynamic accumulators helps, but the hero for micronutrients is seaweed, and the best way I’ve (yet) discovered to process it is by fermenting.

I haven’t found a good way to process seaweed through the chooks. I can chop up a little bit for them, but it’s too tough to chop easily in bulk, if I feed it to them wet, it just mats down and goes slimy and smelly, and if I dry it first, it’s too bulky for them to scratch through. If anyone has discovered a good trick, I’d love to hear it in the comments. Some seaweed gets fed to the worms in the worm farm, but most of it is processed through anaerobic fermentation to make a micronutrient rich tea.

Seaweed has an ecological purpose, so it’s important not to take too much of it off the beach. But you don’t need much – fermenting it makes it go a long way. We collect a couple of buckets full whenever a storm washes up such a lot that our harvest makes no dint. We hose it off to remove the excess salt and sand, then put it in a barrel, cover with water, and let it sit for a fortnight or so.

The barrel has a tight fitting lid – otherwise it’s smelly enough in the initial stages to upset the neighbours. After a fortnight it is fermenting with a slow burble, and it’s ready to use. We dilute about 1:10, and try to get round to giving everything a little bit of it – in the range of half a bucket per fruit tree – every month or so. Sometimes I add some hard-to-manage weeds, like madiera vine, to the barrel too. The fermentation kills any seeds and stops them resprouting. When seaweed was in shorter supply, I would also top the barrel up with nettles or other weeds.

Seaweed contains a whole huge range of trace elements and micronutrients such as boron,  zinc, molybdenum, manganese, and cobalt, some of which are a bit rare in our old Australian soils. It’s sorta like a garden multivitamin.