Rescuing a Crown of Thorns (Euphorbia milii) from a Glass Container

A crown of thorns in a glass container with sand drops leaves when watered. Glass has no drainage—fatal for succulents. Repot immediately: pot with large hole, screen over hole (not rocks), 1:1 sand/perlite and well-drained soil, slightly moist. Water when soil dry to touch. Winter dormancy (Oct–Apr): cool, dry room, no water—leaves drop, that's normal. Spring: gradual water/light, sunny summer spot. Repot up next spring if needed. Hardy plant, wrong container.