[Michael196]

about to plant some acers, Capillilia ( ithink) have other acers about the site that are planted in ericacious and normal soil, some are booming, some doing ok.

Whats teh optimum soil here? does it matter ?

[James Kilkelly]

Michael196, for best Autumn leaf colour, which is one of the main reasons to grow Acers, you should plant in soil with a neutral to acid pH .
The numbers which represent the pH levels are on a scale of 1-14, with acidic below 7, neutral 6.2-7.0, and alkaline (base) above 7.

If you need to decrease your ph to make the soil more acid, then you can apply sulphate of iron at a rate of 100g per metre squared for each drop in ph point.
Apply the products according to the manufacturers instructions and heed safety warnings especially those concerning the use of protective clothing.