Work out the right soil or compost mix

Standing in front of six bags of compost with no idea which one this plant wants.

Tell me what growing medium this plant needs and how to make it from what is available.

1. **What the plant needs**, in terms of properties rather than brands: drainage speed, water retention, aeration, pH, nutrient level, and how it behaves in the wild.
2. **A recipe** using materials sold in ordinary garden centres, with proportions by volume. Give one mix, and one substitution for each component in case a shop is out.
3. **What not to use**, and why, including the common mistakes: garden soil in pots, too much moisture retaining compost, gravel layers at the bottom of pots.
4. **Peat.** Say whether the traditional mix relies on peat and give me a peat free version that actually performs, noting how it behaves differently when watering.
5. **How to tell it is wrong** after a few months, from the plant and from how the pot dries.

If I describe my existing soil, tell me whether to improve it or replace it, and give a clear recommendation.

Plant:
Pot or ground, and what my existing soil is like:
What I can buy locally:

Routine care. Watering tests, repotting calls, pruning timing, compost mixes, and taking cuttings that root.