u/SlugOnAPumpkin

Before they get planted in Maine, I germinate and grow out my fruit/nut seedling in my backyard in Brooklyn. The problem is I currently only have access to 100% organic matter soil.
I use an aged mix of potting soil, compost, and hay, but I have been experiencing some problem recently which I believe may be related to an overabundance of organic matter. I would like to purchase inorganic mineral amendments to make my growing medium more like actual soil. I know the typical solution is to mix in native soil, but it's not practical to transport soil from the final planting destination and Brooklyn soil is too Superfund-y for my taste.

Question: Which inorganic amendments should I purchase, and in what ratio should I mix them?

Preferably, something I can plausibly buy 25-50 lb bag of in Brooklyn. I would rather not pay $100 shipping for an online purchase of such dense material.

Some options I am considering:

• coarse blasting sand
• sand marketed for concrete mix
• fire clay powder marketed for ceramics
• fire clay powder marketed for concrete
• unscented kitty litter
• basalt (unsure if I can source this locally)

Thanks!

Context (skippable read)

I grow out seedlings (mostly nut and fruit trees) in my backyard in Brooklyn, to be planted in the ground out of state. I used to use potting soil for this purpose but lately I've been adding more and more of my homemade compost. The native soil in my area is not safe to use. Consequently, my growing medium is almost entirely organic matter.

Lately, I have noticed weak performance in my seedlings: very late if not failed germination, and disappointing root growth. Investigating the soil pots at the end of last season, I noticed that the friable, nicely textured compost had collapsed into a compacted sponge. After a bit of research, I learned that I may be using too much organic matter. Even in very old forests, top soil is typically not greater than 50%. I need to add more inorganic to my growing medium

Question (tl;dr)

Which inorganic amendments should I add to my compost, and in what proportion?

Loving this book so far, but I'm having trouble keeping track of the characters. Always tougher for me to remember with audiobook compared to text

Tchaikovsky is actually pretty generous when it comes to providing narrative/character/background reminders, but apparently not enough for me!

Anyone know where I can find a full list of the characters? In particular having trouble keeping track of all the different prisoners and staff. Thanks! On chapter 11 btw.