I think as a generalized statement, that should work very well Arif. But, I also think it would be wise to research the needs of each form of cactus you are starting from seed. Different plants have different needs for germination....some grow well scattered on top of the soil, others require the dark beneath the soil. And some require more heat than others to germinate...some ambient and some need direct added heat, just as some seeds need a chilling time to trigger germination. The more you know, the better chances of success.
