How to Grow Cactus Babies
There are many people, including myself, that cannot stop at one cactus. Since they are easy to grow and are highly attractive, you can find yourself creating a collection before you know it! However, instead of spending money on new cacti, or on seeds, you can grow cacti from those that you already have. Even if your cactus hasn't grown 'babies' (small replicas of the cactus will often grow around the mother), you can still grow new cacti from the ones that you already have, provided that they are healthy. This is fantastic for those who don't have much experience growing new plants and thus don't want to spend money on seeds out of fear that they will fail.
If your mother cactus is surrounded by large babies then you will find growing new cacti the easiest. Simply (remember to wear gloves or use something to protect your hands!) separate the baby from the mother, trying to gather as many roots as is possible, and then re-pot. If this has caused any scarring to the mother plant then you may want to use horticultural sulphur powder - this will ensure that no fungal infection can manifest itself where the plant is damaged. The pup should be planted in a mixture of soil and sand, or gravel, to ensure good drainage. Calcium carbonate is also a fantastic addition to ensure that your cacti thrive to their full potential.
You may find, however, that when you try to separate the baby that it simply comes or snaps off, with no roots to be seen. Don't worry, though - this can still be grown, but will instead be treated as though it were a cutting.
Taking a Cutting
Firstly, in order to take a cutting, you'll want to protect your hands. Looking at your cactus, find a section which looks healthy. This may be at the head of the stem or, if your cactus has arm-like branches, these could alternatively be removed. When taking the cutting, make it as smooth as possible - using a sharp knife will be beneficial here to ensure that there are no rough edges. You must also sterilize the knife beforehand, to avoid infection in the plant.
Planting a Cutting
Before you plant your cutting, you will need to wait until it is ready. Leaving your cactus cutting somewhere shady, give it time for the wound to callus. Depending on the size of your cactus cutting this could take anywhere between a few days and a few weeks. Most people leave their cutting until it has started growing roots, at which point they begin to think about potting it. Ensure that you turn your cactus every now and again so that it doesn't grow roots only on the side that you have lying down as well as to avoid curvature of longer cuttings.
Using the soil and sand/gravel mixture as mentioned before, once your cactus cutting or baby has roots it can be planted up. Ensure that it has enough drainage holes and try to keep your cutting away from direct sunlight for a while - if kept in the sun your plant will need more water and may sunburn. As soon as your cutting has been planted you must water it and continue to do so each time the water becomes dry, doing so sparingly. Once your cactus feels steady and signs of growth are evident, you can begin looking after it as normal.