Posted: 13/06/2017 at 12:11
I've always used a mix of two-thirds sieved topsoil and one third well rotted manure. The top soil is available in bags garden centres or in larger quantities from specialist suppliers ... be sure the soil is sieved as recently some posters have received soil from 'cowboys' which has contained the roots of perennial weeds.
Providing the manure is well rotted and mixed with the soil there should be no problem with planting straight away.
If the manure isn't well rotted I would buy some in and use the horse manure stacked or use as the start of a composting system in your new garde.