The slag can also be planted with orchid.

Scum. Such as coal cinder (be careful not to be mistaken for coal ash), bagasse, cotton dregs, shell dregs and so on.

Coal cinder is very light, it can be smashed to make it like sand, sift out its slag powder, rinse it repeatedly with water, reduce its fire gas, and then mix it with bran material, which is convenient and economical, and the planting effect is good, but the cinder is highly radioactive and should not be used indoors.

Bagasse should be washed repeatedly, removed its sugar, then chopped, and retted for about a year before it can be used. It can also be mixed with other plant materials.

Cotton dregs are the leftovers of textile mills, and some are mixed with a small amount of cottonseed, which can be mixed with other plant materials after retting.

Shell dregs are common by the sea. After washing off their salts with water, they can be burnt with fire or humus soil or pond mud mixed with 2 + 10.

The slag is characterized by looseness and light weight and drainage. The water conservators can be all right. But the residue itself is less fertilizer, so pay attention to timely fertilization.