I bought a starter kit with 4 different tree species and some are getting big enough to be repotted into their own planter. I’ve done some research and found that different tree types require different soil mixtures, but I want to make sure I’m getting the best soil for each of my trees. If it matters, I live in the suburbs of Philadelphia - we get all 4 seasons, our Summers get hot (it can approach the mid/upper 90s on some days, but usually stays in the 70s or 80s) and our Winters get cold (it can approach 0 degrees sometimes, especially with windchills, and snow is pretty consistent).

So my question is - what kind of soil do I need for...

1) Delonix Regia?

2) Black Poui?

3) Pinus Aristata?

4) Picea Abies?

I prefer ordering through Amazon, unless they really have nothing or there’s a much better alternative. Thanks in advance!

Please check the link below:

www.growingbonsai.net/characteristics-of-good-bonsai-substrate/

NOTE: Delonix Regia is a tropical, so winter protection is needed.
and...
some organic component in your mix can help it feel happy.
From Amazon, a good choice in general is:
www.amazon.com/Boon-Bonsai-Soil-Mix-Inorganic/dp/B0762XY4BB