The main consideration when growing cacti outside in the UK is choosing the position that would best suit these plants.
The ideal position would be a sheltered south/southwest facing aspect of the garden. Most positions will be adequate as long as they are in full sun for most of the day, encouraging a warm well drained microclimate (I have cactus against an east wall that grow well but do not flower).
A cactus bed is best placed against a wall of fence to offer shelter from cold winds and encourage reflection of both solar heat and light (but not vital). If the site can be constructed in a manner as to slope towards the south, this will encourage a warmer microclimate ideal for the hardy cactus.
The site should be away drain outlets or known drip areas such as under roof eves as this will encourage the growing site to be excessively wet during the winter months.
WARNING
AN INPORTANT CONSIDERATION WHEN CONSTRUCTING A CACTUS BED AND GROWING CACTUS IN THE GARDEN IS TO LOCATE THEM AWAY FROM ANIMALS AND CHILDREN. MANY OF THE CACTI THAT ARE HARDY HAVE LARGE DANGERIOUS SPINES THAT ARE VERY SHARP. THEY ALSO HAVE HAIR LIKE SPINES CALLED GLOCHIDS WHICH ARE LIKE FIBRE-GLASS AND CAN CAUSE GREAT DISCONFORT IF THEY COME INCONTACT WITH THE SKIN.
