Most cacti and succulents do best in pots that are quite small in proportion to the size of their top growth, so if you decide to repot them, move them into a pot that is only one size larger than the one they are in. always use plenty of drainage material in the bottom of the pot.
Repotting a prickly cactus without injury is a tricky job. Handle it using a folded strip of paper, thick paper or thin card. Make a flexible band that you can wrap around the plant and use it as a handle. Carefully wrap it around the plant and hold it firmly. Tap the pot to loosen the rootball and lift the plant using the paper band. If it doesn’t come out try to push a pencil through the drainage holes to break the bond.
If the plant has been in the same compost for a long time then crumble away a little of it from the base and around the sides of the rootball trying not to damage the roots. You can also remove loose compost from the top of the rootball. Hold the plant into its new pot using the paper band and trickle a suitable compost around the old rootball. If the shape of the plant does not allow you to do this without touching its spines then you should use a spoon to add the compost. Tap the bottom of the pot on a hard surface to settle the soil around the roots because it is often difficult to firm the soil with your fingers if the cactus is prickly. Wait a couple of days before watering.
If you are planning to plant a cactus bowl for a table display instead of just repotting each individual plant then you must select plants that require similar growing conditions. For example most desert plants are compatible and most rainforest ones will grow well together but never mix together the two groups. Also separate winter flowering Christmas cactus.
Stand the bowl in its eventual home and place the plants still in their pots into the bowl and arrange them for the best effect. Try not to overcrowd the plants or the container will soon look overgrown and will detract from its overall appearance. Arrange the plants for shape, style and color to have a pleasant arrangement. Put plenty of drainage material in the base of the bowl then fill with cactus compost and plant the specimens, firming in well. If you want to add a touch of a more natural look you can add some pieces of rock. Top-dress with fine gravel. Use a paintbrush for leveling the gravel and pushing it around the plants.