The next five pictures show how to pot up single cuttings into individual 4" pots:
Fill the 4" pots about half full with your favorite epiphyllum mix. This potting soil can be "bag moist," but no wetter. Remember that until your cuttings have developed some roots, wet potting soil will only cause them to rot.
Firm up the potting soil lightly with your fingers. Don't compress too much, just a light touch is all that is needed.
Pot up a single cutting in each 4" pot. Hold the cutting in one hand and fill in more potting soil with the other hand, firming it up slightly as you go. Plant the cuttings deep enough so that they don't tend to tip over and fall out of the pot while they are rooting.
Continue until all of the cuttings are in their 4" pots. Be careful that you are planting them the right way around with the areoles pointing up. By the way, an epi cutting that is planted upside down will probably still root. However, it will not grow as vigorously as it would right side up.
All done! You will want to situate your newly planted cuttings in a place that receives very little direct sunlight. Remember, these plants do not yet have a root system and therefore cannot absorb moisture from the potting soil, so too much hot sunlight will only cause the cuttings to dry out so fast that you may see them begin to shrivel.
The next four pictures show how to pot up multiple cuttings into a single 6" pot:
Fill the 6" pot about half full with your epi mix. Again, the mix should be no wetter than "bag moist."
Many epi growers are impatient and desire a blooming plant as quickly as possible. This is understandable. One way to speed things up a little is to root three or more cuttings of a single epi variety together in a 6" pot. Epis like to be root-bound in order to bloom and three rooted cuttings will become root-bound more quickly than a single cutting. Three or more cuttings rooted together will also give you a nice big specimen plant quicker than a single cutting. It is important to make sure that all the cuttings rooted in a single pot are of the same variety. Some epiphyllum varieties are vigorous growers and some are not so vigorous. So, if more than one variety are rooted together in the same pot, the most vigorous will become dominant and will tend to crowd out the lesser grower.
Firm up the potting soil lightly with your fingers.
Space out the cuttings around the pot as evenly as you can and fill in around them with more potting soil, firming it lightly as you go. Again, make sure they are planted right side up and deeply enough so that they don't flop over.
Complete! Again, place your cuttings in an area that in not too hot or too sunny until they get some roots. A few weeks after potting up your cuttings, you may be wondering if they have rooted. You can test this by gently tugging on a cutting. If you feel some resistance, the cutting has probably rooted. If the cutting is showing any new growth, you can be certain it has rooted. Once you're sure some roots have developed you can begin watering your epi like you would any other plant. Water thoroughly so that excess water runs from the drain holes and then let the plant dry out pretty thoroughly before watering again.