Originally Posted by lannerman

Hi rajah, yes, the concrete will have had some bearing on the ph and also the fact that the soil has been under this concrete for awhile will also tend to make it more alkaline. I feel that your natural ph must be high, have you checked the ph of the soil away from the shed base to compare ? Its very hard to change basic ph levels and I'd suggest that you plant things which like lime. Having done what youve done re the sand and FYM, you can plant when ever you want, theres no reason to leave it.
regards, Lannerman.