More about San Pedro Crested
Usually, this variety ends up in a comb-like shape which, as seasons go by, can multiply into many comb-shaped heads. The possibilities are infinite nevertheless, so no cactus will ever be the same as another. What this means for you is that, unlike the standard San Pedro, with this variety you never quite know how the cactus is going to look as it matures.
As each of the growth points develop at a different pace, the overall cactus ends up forming all sorts of shapes. A faster growing point that is adjacent to a slower growing point will likely lead to a slightly more slouched cactus; whereas growing points that move all at about the same pace will make the cactus adopt a more vertical position.
The crested San Pedro is originally from the mountains of Peru, Ecuador, Bolivia and northern Argentina. As such, it is used to colder temperatures, which can go as low as -12 °C. Don’t think that because of that, however, you have a free pass to leave the cactus outside during the winter season. Although the cactus could withstand such temperatures, you should always aim at keepin it at temperatures above 5 °C.
When it comes to water, this cactus is also a bit different from the rest. Unlike most cacti, the crested San Pedro can take larger amounts of water. In fact, some would say it can even be treated as a normal plant. It is never good to overwater it,however, so always keep an eye at the humidity of the soil. Make sure the soil is well-drained and fertile!
As for the sun, you can think of the crested San Pedro as another human. It sure loves the sun, but not too much of it. During the summer, it is a good idea to let the cactus catch some direct sunlight but don’t let it catch too much of it as this might lead to sunburns. During the winter it is nice to leave it somewhere it can still catch some bright light. As the light during winter will never be as intense as what you get during summer, however, you should consider letting the cactus enter dormancy by reframing from watering and fertilizing it. As the light levels are lower during winter, the cactus might lose weight if it doesn’t enter the dormant phase!
After delivery, place the unrooted cuttings in a pot with dry, well draining cactus soil and place them in a light spot but not in direct sunlight. After about a month, you may give it a little bit more sunshine and very carefully start watering the cutting.
Make sure that you don't overwater the plant before it has roots and let it get used to full sunlight gradually to prevent sunburn. Allow for the soil to dry out between waterings, in spring or autumn you're going to water less then in summer and in the winter you don't need to water your cactus at all.
Echinopsis pachanoi (= Trichocereus pachanoi)