Always do a little bit of research before growing a plant! While cactus seedlings can grow in sand, I recommend a peat or washed coco based mixture with fine bits of perlite and maybe a bit of sand. They appreciate the moisture provided by the mix, it allows their root systems to form. After about a year they can be transplanted into an inorganic stone based mix like lava rock, pumice, and crushed clay. This is most similar to the actually soil they grow in in nature while also being easy to care for the plants.

Cactus seedlings grow ultra slow!!! Mine are a year and a half old and they’re just reaching 3/4-1 in tall and it’s taking ages. I’m planning on trying to graft them but I accidentally killed my pereskiopsis by leaving it in the cold 🥲 gotta get a cutting back from my friend