A few things to note:
There are now many variations to subs supersoil over the years so its best to specify exactly your plan.
I did the “original” mix and had great results however I had leaf yellowing a few weeks into flower which became known as a common problem due to K deficiency. So plan on adding some K to the mix like langbenite.
He calls for 0-5-0 guano and stick to that because I used a few 0-10-0 and my soil test after harvest showed the P was SKY HIGH so you may not need to add alot of P in flower like you stated above even at the 0-5-0 rate.
Use more compost, EWC and aeration than he calls for.
Going forward i’m using “coots mix” which has IMO a better mix of ingredients and no guanos. I also like that the mix is the entire pot instead of just the bottom layer as in subs mix. That layering is tough to reamend IMO because you have fully depleted soil in 3/4 of the pot and a hotter charge at the bottom. Nothing against subs mix at all, Ive seen great results and it was my segway into living soil and I appreciate his work for that.
This was the OG recipe im referring to.
There’s nothing that compares to the flavor of properly grown organic pot: The subtle tastes and aromas created by using only “Mother Earth” are overwhelming to the senses when it’s done properly. As with vegetables, a rich organic soil can bring out the best in cannabis. Over the past 20 years...
hightimes.com