In my opinion the white fungus on the top of the soil is all good. If it starts growing on the stock i would be concerned. Sounds like you really like that potting soil you are using. Thats a good starting point for the base of a custom soil mix.Also, a very very important part is worm castings. And when it comes to castings;the fresher the better. Thats why i got my worms and built a box for them about a year ago. They are great recyclers and the end product is pure gold. The other part of the base is coconut coir. I use Botanicare brand as its OMRI listed and very well rinsed so its ready to use out of the bag. Sustainable, enviro- friendly, great water retention, neutral pH and the list goes on - great stuff. And for aeration use plenty of small-nugget perlite. Very important to have good aeration as im sure you know. Man, im hooked on building my own mix and its become an obsession finding and purchasing all the necessary amendments. When i first started i had a hard time finding alot of the stuff. Things like bone and blood meals, dolomite lime and dry all-purpose can all be found easily at places like walmart and home depot. As for the other amendments, this is where it can get tricky-at least it was for me. My first build(currently in use) i was lazy and strapped for cash. I had my worm castings and some basic stuff but wanted to really get started so i said fuck it, mixed up a batch and let it cook for about a month. This is what it looked like:
6gal bag black earth
2gal coco coir
2gal perlite
Amendments:
2 cups dolomite lime(prilled)
1/2 cup blood meal
1 cup bone meal(regular)
1/2 cup bone meal(steamed)
1 cup dry all-purpose(4-4-4)
1 cup crushed eggshells
1 cup brown rice
5 cups steer manure
Notice i dont have any worm castings in the base. Well i fucked up there. Always get some in there. What i did was mix it in prior to transplanting. Still ok but they really should be in at the start as well to inoculate the batch with all kinds of good stuff. I also cut with more coco coir and perlite just prior to transplanting. This made my mix even weaker than it already was and was quickly sucked dry of all available nutrients. Also, the mix overall is extremely lacking in trace elements and micro-nutrients. So i started thinking of my amendments as building blocks and that i could build a much better structure with more building blocks(amendments). So my next batch is now going to look like this:
6gal bag black earth
2gal coco coir
2gal perlite
2gal fresh worm castings
Amendments:
2-1/2 cups dolomite lime(prilled)
3/4 cup blood meal
1 cup bone meal(regular)
1/2 cup bone meal(steamed)
1-1/2 cups organic dry all-purpose
1 cup crushed eggshells
1 cup greensand
1-1/2 cups alfalfa meal
3/4 cup kelp meal
1/4 cup soft rock phosphate
1/4 cup rock phosphate(granular)
3/4 cup feather meal
1/4 glacial rock dust
1/4 cup neem meal
1/4 cup high N bat guano
1/4 cup high P bat guano
1 cup brown rice
5 cups steer manure
Quite a drastic change and while i dont know for sure yet, it should be evident in the overall quality of the next run. Even still i am suprised at how far i have come since making that first batch and am really looking forward to finally smoking some truly organic cannabis. Just can hardly wait till the next run! Sorry this is so long bro, coffee and hoots plus i could talk about organics all day man. I even dream about soil, its fucked up. But anyways, hope at least some of it makes sense and take care buddy.
