Wrap a folded strip of newspaper around the top of the plant. This will help you slide it out of its pot and maneuver it into the larger planter without getting spines or fine hairs in your fingers. It also protects the plant.
Fill in the gaps
Once the plants are in position, use a spoon to carefully fill the gaps between them with a cacti soil. Add small amounts of soil at a time and keep firming it down with the back of a spoon to ensure that there are no air holes left around the plant roots.
Brush off soil
No matter how careful you are, some soil will inevitably get caught in the cactus spines and hairs. Use a soft brush to remove it and to keep the plants looking clean and neat.
Water all the plants in well. In summer, they can be watered whenever the surface of the soil dries out. In winter, they should be left dry; start watering again sparingly when you see signs of growth in spring.
Apply a sand mulch
Use the spoon to spread fine sand around the surface of the planter. This helps water quickly drain away from the surface, preventing rot, and gives the planter an authentic desert like appearance. Set your arrangement in a bright, sunny position.
Reprinted with permission from How to Grow Practically Everything. Copyright 2010 by Dorling Kindersley.