advice on preparing soil under old concrete shed base

[rajah99]

Hi

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?

I intend to plant a Cycas revoluta, musa basjoo, black bamboo and grapevince (boskoop glory) in this patch.

many thanks for any assistance.

[jungle jas]

The chemicals in the dust will eventually wash down through the soil, and will leach out of the lumps eventually over a period of time. I have no Idea how long that will take! Rake out as many of the concrete lumps as you can. I am told pine needles are very acidic try them! You need to test the soil to find out what P H you have .Why knock you self out? plant some lime loving plants.

[rajah99]

Well its only because i bought the plants already.

However, i just finished testing soil in various parts of the garden, and found that its almost neutral to alkaline everywhere.

Ive already got a trachycarpus wagnerianus and a musa basjoo growing happily in that soil, so maybe what im intending to plant wont mind the soil.

Ill probably add some more compost and perhaps a few bags of top soil to the underlying soil before planting.

thanks for the feeback.

btw, any favourite tropical/exotic types that love lime?

[GREVILLE]

If you keep your soil free draining it will always tend to acidifiy. Composted bark helps and makes the soil very workable. If you are worried about too much lime affecting acid -loving plants you can always play safe and water in Miracid around your plantings.

Musas have a preference for slightly acid soils but will cope quite well with alkaline.

I believe Brahea Armata likes lime.