I am doing my first attempt at growing seeds in a controlled environment (sterile soil and humidity box, i.e. the classical method). So far, I've been collecting plants from seeds which fell around the mother plant and sprouted. I never had the incentive to grow many seedlings from a plant which I already have in my collection, and I just recently find a reliable source of seeds by variety.

Once I'm familiar with the fine-tuning of this method, I will start sowing the more difficult varieties. Some varieties may fail to grow at first attempt, so I plan to graft the seedlings for better results. How fast can I do it? Is it OK just to open the humidity box and take a cactus for grafting?