I’m starting sweet potatoes from saved tubers. I’m seeing this odd white crystal stuff on some of the leaves again. Does anyone know what this is? It seems to kill the leaves eventually. The plant usually seems to outgrow this.
Sweet potatoes are among the vegetables high in calcium oxalates, which can be exuded through plant pores (stomata) under certain conditions. It will form sand like crystals when it dries. The mechanism is not exactly like guttation in which a function of hydathodes exuding excess internal water.