Cheap, homemade fish hydrolysate, very easy with the right ingredients and equipment, although very messy and certainly not for the squeamish, LOL
Recipe, taken from here
http://theunconventionalfarmer.com/recipes/fish-fertilizer/
I used 2 mackrel bought for £4 from the local supermarket, each 'measured' as roughly 500ml in volume, so I followed their recipe to the 'T'
'1' Mackrel 500ml (to measure the fish volume, I poured 300ml of water in a 1 litre jug and added the cut up fish, the water level went up to 800ml, so I knew I had 500ml of fish)
1500ml water (non or de-chlorinated)
167g mollases/brownsugar
4 tablespoons of lacto/em1 (I'm not 100% confident in my homemade lacto, so also used some EM1 for piece of mind)
It's really important to cut up the skin of the fish into small pieces, if you don't want to be replacing your blender, it's totally disgusting, but better than paying for a new blender. The skin in particular wraps around the blades, straining the motor till it burns out. Blend the fish in small bursts and monitor how warm the body of the blender is getting. If you smell any burning, that is the motor, stop immediately and allow everything to cool down.
Put your fish, (some)water, sugar and lacto in the blender and blend till you've got a fine mush
Pour into a large bottle with the rest of the water, mix up and allow to ferment in a warm, dark place for 4-6 weeks. It's important to keep it as anaerobic as possible, but it's also vital that you release the gas produced during fermentation somehow. I really wouldn't like to have to clean up an exploded bottle of this stuff, LOL When it's ready, the nasty fishy smell is gone and you're left with a faint sweet/vinegary smell
