I do something similar to
except using PVA glue. A generally "old school" look.
I finish the model.
Paint the base the a darker "under" colour. Usually a dark green.
Spread PVA glue+water (70/30 ish) on the top of the base using an old brush with very short bristles.
Immerse the base in a mix of gravel ballast. I use a mix of two different grits. Ensure the ballast covers the glue.
Remove the model from the ballast and let dry.
Angle the model's base over the ballast and tap the side to shake loose any unfixed gravel.
Paint the gravel with a thinned out layer of the basing under colour.
Highlight by 'wet' dry brushing with a lighter colour. E.g light green.
Add a dry brush with an even lighter colour. E.g. green-yellow.
Finally I repaint the base rim with light green to match the green table.