BW I go to the natural gardener all of the time and I use the Ladybug fertilizer concetrate on my elephant ears that I have.
The Plants are in 40 gallon tubs without holes so i dont want the soil to build up with salts from a non organic fertilizer.
In short the stuff works real well and I would think the stuff you want would work too.
But I have to ask how much is the cost of 2 cubic feet of the soil?
By the way there is 7.48 gallons in one cubic foot. so a bag will fill a 15 gallon container.
Worth