I’ve heard from guys that use MG to just throw a couple shovels in the bottom of the hole and maybe mix a bit in up top. The problem is that the organics decompose in the ground, using up oxygen, lowering redox, etc. If you mix it completely through and get a heavy rain and it compacts then you have issues. Then there is bugs.
In my sandy loam I cannot believe how good loaded biochar works. I mix it very lightly through my soil. Usually load it with something stinky because it makes the smell go away. Fish filter waste, rotten fruit, etc. It’s a good way to deal with stinky waste. The organics adsorb onto the charcoal and the smell will be gone when it dries. I’m going to try bone charcoal this year, homemade. I just make a fire and then hose it.
If you try an experiment put half in the miracle grow and half straight in the dirt with a little top dressed organic tomato granules and a
fish buried a foot and a half under the root ball, and a tea or two. I guarantee you will never grow with miracle grow again. Stronger plants = less pests. Btw if you put your pests in your tea you will breed their enemies.
A local outdoor grower told me a story last year. He grew in an old pasture clearing in a forest, that had black dirt, never been cropped, fertilized or sprayed. Every year it was easy for him. So last year he wanted to go a little more commercial so he went and bought some miracle grow shake and feed. He ended up with his worst yield and most problems ever.
To get your yield get some decent outdoor genetics, and do the training to open them up. Be mindful of how clean your yard is where you put them. I always dig and inspect the dirt for traces of burnt garbage to make sure I’m not growing on an old garbage burn pile or something. The plant will remediate soil by pulling the toxins into the plant. Many pesticide residues can be removed with various bacillus sp. in bennies, septobac, and other similar products if you are worried.
If you have blueberries growing on the local farms you may find addition of minerals to be of benefit. Crushed dolomite lime, crushed basalt, calcined montmorrilite clays (special kitty). The rain tends to wash these minerals out of sand. Another thing worth considering in agricultural areas is that hills are cleaner than low spots. A place in a field where water collects will also collect pesticide residues, which is noticeable in the poor growth of the plants in that area. The farmer says it’s because of the water that sat there in spring but this has been researched and found to be true. To anybody that plants in cornfields still (?) glyphosate has a half life of 58 days in soil, yet it can be digested fairly quickly with Bacillus subtilus!