In message , Don
writes
I have just bought myself a 6 x 8 Elite Craftsman greenhouse which,
after something of a struggle, I have now finished erecting.
There is no provision for locking the door or fixing a padlock, though I
believe Elite do sell such a thing.

Not worth it. Though it is worth considering how to lock down the door
and any opening windows so that they cannot be sprung out by winter
storms. And also consider strengthening the cross struts on the corner
that faces into the prevailing wind. That was what did for mine...

What sort of security do amateur gardeners usually install in or on
their greenhouses?

None.

Regards,
--
Martin Brown