There are websites that give instructions about how to do this, but I don't think it's quick or easy or cheap - or long-lasting! If you have alkaline soil you can grow acid-loving plants in pots, or have a try in raised beds with large amounts of peat in, and water with sequestrene-containing plant tonics, but it would be far easier to accept that you have alkaline soil and grow the plants that that suits.

The pine tree you want to grow should be small and slow-growing (picea pungens hoopsii) and ought to be OK in neutral to acid soil. If yours is strongly alkaline why not plant it in a pot?

The only way it can be done is to remove all the soil you have and replace it with a soil that is acid. I've only been able to do this with small areas.

In the UK, alkaline soil probably means chalk or limestone underground, which will make lowering the pH of the soil difficult and temporary. Better to plant your acid-lovers in large containers or raised beds!

Mickyt if this is a follow on from your earlier question I don't think you really can. As said above you'd have to remove all the soil and even then the underlaying soil would not be acidic. You just need to accept that you have to grow plants that do not require acidic soil or move to a different part of the country. We are extremely lucky as our basic soil is neutral so we can work it up to acidic or alkaline as we need.