Can I sow grass in gravel grids?

No, gravel grids are not suitable for grass. For this purpose it is best to use a grass grid, such as ECCOdal.

Gravel grids have a tighter mesh than grass grids, making it more difficult to sow grass in them. Gravel grids also have a geotextile that serves as an anti-rooting mat (to counter weeds), making it more difficult for plants and grasses to attach. This keeps your gravel surfacing free of weeds for a longer period of time. With grass grids, a synthetic base is provided with specific properties for seeding grasses.