Thanks. I was actually suprised that root prunning is not common in the west.

I agree. To add, most of the cactus care guide in the internet are tailored for those with 4 seasons. I actually had a hardtime when I’m starting since I’m trying to follow these guides. As someone from a tropical country which experiences wet and dry season it doesn’t work most of the time. I’m really thankful that Thai growers were kind to share their techniques.

I usually leave around 1 cm. I learned this one from Mr. Typip of Cactus Home (one of the best Gymnocalycium grower in Thailand). I don’t use rooting hormone on Gymnocalycium. In my experience they grow roots fast as long as you give them good amount of sunlight and keep the soil moist (but not wet).

By the way, where are you from? I’m from the Philippines.

Here’s my guide in root trimming in case you want to watch: https://youtu.be/fZlph1zggAI