Does greenhouse work have radioactive substances?

Answer 1

No radioactive substances are used for ordinary greenhouse work beyond what is found in nature.

Radioactive substances are controlled very closely by governments - in the US, it is done by the NRC. Licencing and training are required to work with such materials. They are not the sort of thing workers would encounter without being told.

There are radioactive substances found in nature, but the level of radioactivity is usually considered insignificant, and they are nearly always no different than levels people might encounter in any ordinary workplace or home.