A question on implicit grids

Will the code below automatically create rows for the named grid areas or should I specify the rows as : 1fr 1fr 1fr 1fr?

.grid{
display:grid;
grid-template-columns: 1fr;
grid-template-rows: auto;
grid-template-areas:
                               "nav"
                               "header"
                               "content"
                               "footer";
}

It should. If you want to see the grid you can the developer tools. Firefox has a pretty neat grid inspector.