Desert cacti (and succulents) make a great plants for those who tend to neglect watering, since they need little if any water once established. However, they do need bright light. Jungle cacti (such as Christmas cactus) and succulents need a moister soil (and not as much light) but even they need less than most plants.
Cacti and succulents can be repotted at any time of the year. Many succulents present no special handling problems, but prickly cacti have to be treated with respect.
If possible, choose a soil mix formulated for cacti, as this will be well drained and have the right sort of structure and nutrient level. A soil-based potting mixture is a practical alternative. Some commercial growers use peat-based potting mixtures, but these are best avoided. Apart from the difficulty in keeping the water balance right, peat-based potting mixtures do not have the weight and structure to support large cacti and succulents.
Large specimens do not need regular repotting. Simply remove about 3 cm (about 1 inch) of soil from the top and replace with fresh cactus soil.
To handle a prickly cactus, fold a strip of newspaper, thick paper or thin card to make a flexible band that you can wrap around the plant. Tap the pot on a hard surface to loosen the root-ball. You can then often lift the plant out with the improvised handle. If it refuses to move, try pushing a pencil through the drainage hole to break the bond.
If the plant has been in the same soil for a long time, crumble away a little of it from the base and around the sides of the root-ball. But be careful to minimize damage to the roots. Just shake off loose compost.
The majority of cacti and succulents are best grown in pots that are quite small in proportion to the size of the top growth. It is usually best to move the plant into a pot only one size larger. If using a clay pot, cover the drainage hole with pieces of broken pot or other material.
While holding the plant with the improvised handle, trickle compost around the old root-ball. With some cacti, their shape makes this difficult to do without your hand touching the spines, in which case you can use a spoon.
With a little care in handling, you will have a plant ready to go on decorating your garden for some time to come.