Dear Patrick,just I have take a look at the documentation of pgfgantt (http://texdoc.net/texmf-dist/doc/latex/pgfgantt/pgfgantt.pdf). If you mastered the package and you can live with the ERT produced, then there is nothing to be said against it that you can use it.
Otherwise do it so, as I have described: using an external application to make the Gantt chart, generating therefrom an image and embed the image into LyX.
Best regards Marcus -- PMs to: [email protected]
