Add oine needles and oak leaves and some Miracid a type of Miracle Gro product.

Pine needles sorry for the typo.

Where on the PH scale is the soil? Do you mean it is actually alkaline? or do you have mid-range PH soil that you need to make more acidic to grow certain plants?

You know what they say about organic material [OM] ... it helps to correct for both too acidic and too alkaline. Same is true of compost and vermicompost.

How large is the container? If it's really large, sulfur may be your best bet, although that can take a long time. If it's smaller, some kind of fertilizer that is marketed as being for acid-loving plants may do what you want.

What is that soils pH?
What is the Calcium/Magnesium ratio?
Generally sulfur is the best choice of material to use to free up the Hydrogen ions that lower a soils pH. Pine needles, Oak leaves, peaty moss, etc. do not change a soils pH significantly enough to matter.

Aluminum sulfate is also available, I've used that on hydrangeas before.

Aluminum Sulfate could be used but just a wee bit too much can become a soil toxin, like many other chemicals added to soil. And yes even agricultural sulfur could be a soil toxin if too much is thrown onto the soil, but the margin of error is greater with the sulfur then the Aluminum Sulfate.

Many thanks to you all. I should now be able to crack it.

I dislike it when persons say go somewhere else to look for your answer but occasionally I do it myself. May I suggest Gardenweb's Container Gardening forum?