Biochar soil mix ratio. How much biochar to add to how much soil?

I make the soil mix I use for all my gardening. I start with the recommended ratio so you may see what that looks like in a practical application. The 'recipe' for this mix: 1 cubic foot of soil. 12 quarts volume of Biochar. 5 gallon volume of loose compost (cold composted leaf/grass) Please subscribe for easy affordable and sustainable organic gardening! Thank-you my friends!