preparing soil under old concrete shed base

Ive just broken up a concrete shed base (around 1.5m x 3m) and want to use the soil underneath for planting. Obvioulsy the act of breaking up the concrete has meant that a lot of concrete rubble and dust been thrown into the soil.

the soil was quite compacted, i removed as much of the concrete and stones from the top, then forked it over to about depth of a garden fork.

At this stage measuring the ph it was heavily alkaline. This could be the natural ph, or it could be due to the concrete.

It was still quite compacted, so ive added sand to it. Also added a lot of well rotted horse manure.

How do I go about reducing the ph, to make the soil slightly acidic?

will the concrete mixed in the soil continue to cause problems no matter what i do? Or will adding acid to the soil balance out things and fix the problem?

also what duration of time do i need to wait before thinking of planting in it?

many thanks for any assistance.

The standard measurement of alkalinity and acidity is known as pH. The pH scale ranges from 0 to 14. A pH of 7 is neutral, which is neither acid nor alkaline. Below 7 is acid and above 7 is alkaline. A pH of 5.5 is 10 times more acidic than a pH of 6.5. Conversely, a pH of 8.5 is 10 times more alkaline than a pH of 7.5.

Most horticultural plants grow best in soils with a pH between 6 (slightly acid) and 7.5 (slightly alkaline). But before attempting to raise or lower your soil's pH, you should first conduct a soil test to determine your current soil pH.

The pH of highly acidic soils can be raised by incorporating limestone into the soil. Hydrated lime works quicker, but over liming is more likely. Wood ash will also raise the soil pH and make the soil more alkaline. Do not apply wood ash, limestone, hydrated lime, or other liming materials to alkaline soils. Modifying a soil's pH is usually a slow process and may require repeat treatments. It is often most effective to use a combination of treatments. However, don't expect a quick fix or a miracle cure.