Finally starting adding grass to my son's model railway.
It's an undercoat of brown paint (tester pot of Chocolate Brown from Wickes), with static grass scattered over the top. A layer of PVA was added and spread all over, then the grass gently shaken from a small sieve to build it up. After the glue had dried a mix of water and PVA glue was sprayed over to seal the grass and stop it falling off. Some green lichen was then glued along the edge of the embankments to represent small bushes. Lichen will be added to the hill to help cover the gap between the slope and the removeable top, and also randomly on the slope. Lots of lichen will be added around the car park to form a thick hedge and to cover much of the ground around the trees where adding grass will be awkward.
Hopefully the areas at the lower edges of the grass on the hill and the embankment by the bridge where it appears white will fade over time, as the PVA should dry clear when fully cured. The hill doesn't look quite as patchy in real life, the flash on the camera makes the grass look thinner. If it is too thin it'll get another layer, there are still areas around the houses that need grass adding once a large bag has been obtained.