Lophophora fricii - here in flower - is relatively easy to grow. It prefers a slightly basic soil with almost mineral content but it may accommodate, as in this case, some worm compost and even coco coir. Say 20% of the total soil mix. Another addition was perlite... too bad it tends to rise up at the surface when watering is done from above.
By the way, watering is sparse. Say twice a month when the weather is fine - that is over 28 degrees Celsius - and no high atmospheric humidity is encountered. Too much water will make it burst. It can take quite a lot of sun and cold if grown hard.
My understanding of the concept of hard growing will be explained later on.
