Growing pseudolithos in coarse quartz sand. Do plants need to be fertilized?

I sowed Pseudolithos migiurtinus two weeks ago.
The nursery where I bought the seeds recommended planting them in pure mineral substrate with no any organic component.

I sowed the seeds in coarse quartz sand. The seedlings have sproouted quite well, 17 out 18 seeds. One of them is still hard and wasn’t infected by mold, so there is still hope to get 100% germination rate.

The seedlings start growing, but they are in pure sand, with no any mineral substances required for successfull growing. Yes I know, many succulents grow in very poor soils, but not completly empty of minerals.

So, should I start fertilizing them? What fertilizer and what dose can I use?

Using pure coarse sand should prevent mold and rot, because Pseudolithos is very vulnerable to these hazards, but I’m worried that growing can be stoped due to lack minerals.

by GefoSiY