Alfalfa from a pet store for like 6 bucks lasts for ever and works great npk of 5-3 1 2 perfect for MJ.
I put two cups of water in a blender a capfull/tbs apple cider vinegar, a b-complex vitamin, a salmon oil cap, a tbs molasses, a tsp epsom salt half a teaspoon of aquarium sea salt then I keep adding alfalfa hay into the blender and blend till I have 3 cups total in the blender one being alfalfa. Then pour into a gallon milk jug wash out the blender but put all of it in the gallon jug then fill but leave an inch or more for it to ferment shake every day don't cap it tight.
It can be used right away but much better if fermented for a couple of weeks it will get nice and stinky but then mellow a bit with low ph then use 1-4 cup of the concentrate to a gallon.
I also do the same thing with shake leaf, oatmeal. coffee or earth worm casings just shake up the concentrate really good so some sediment is in every cup so there isn't much left at the end it can be used as top dressing it works great the oatmeal and EWC are balanced NPK for late flowering and as a change during veg the others are high nitrogen.
I use more alfalfa for most of my feeding because of the growth hormones, with these set concentrates you can feed every time adjusting the strength as the plant gets bigger.
Also I have given milk 2 tbs to a gallon it is a balanced npk for flower.