Brush on some kind of watery adhesive. You can use Woodland Scencs Scenic Cement
Or you can mix white glue (PVA Glue) with water. I typically mix them at 50/50 percent.
Woodland Scenics Scenic Cement
Then shake your grass material onto the landscape. The wet glue will hold it in place. One of the best ways to shake the material onto the landscape is to simply put it in a folded piece of paper. When the liquid cement dries the landscape material will be held firmly in place.
I have used store bought texture for this. You can make your own textures by mixing sawdust with watered down paints in a variety of colors.
If you want to make your own terrain textures I have some great tutorials for this.
How to use cork to make great looking rubble on your diorama
This is terrific for battle scenes, or broken down and run down towns and areas of your diorama. Cork is very useful and looks great. Here is the complete tutorial including painting tips and a video. Rubble Diorama
How to make your own terrain textures
It is easy to make great terrain for dioramas and wargaming. All you need is foam, a rasp and some paint. I show you how right here. Make terrain textures out of foam
How to make terrain texture out of pencil shavings
Yup, great way to turn pencil shavings into terrain of any color and consistency. How to make pencil shaving terrain
Continue with the different types of landscape. Sprinkle on brown for the dirt and small stones. This closeup shows a variety of materials that have been glued into place by sprinkling. The gray areas are predominantly rock so I have painted these a second time, washing gray and white into them.
A variety of materials can be used to get this general landscape effect. You can use real soil! small pebbles, sand, Sawdust and scrapings from a variety of foam and styrofoam. Be creative. Dye your material and apply them.
Periodically you should cover the work with a liberal spraying of glue. Put glue in your spray bottle and spray the area you are working on. This assures the materials stick to the board and to each other. I use both the scenic cement and my mixture of 50/50 white glue and water in the spray bottle
Let's move on to chapter 5 "Creating and adding stones and rocks"
Field Grass, Light Green
This is what I use to make the clumps of grass in the tutorial. I also have a tutorial specifically about making tufts of grass
Fine Turf Shaker, Green Grass
Comes in Shaker. Ads texture and highlights to trees and scenery. Available in six realistic colors, which model fresh, scorched and dying grasses, weeds and dirt roads. This is perfect for laying out grass on your diorama or terrain. You just brush or spray white glue onto the surface and sprinkle this on. This container holds a lot of material so you will get a lot of terrain coverage out of it.
Terrain Modelling (Modelling Masterclass)- This title helps modellers who wish to display the results of their efforts to the best advantage in a diorama. This book provides detailed information on how to create many different types of terrain; the paints, glues, tools and materials that will be of help to the modeller; and how these can be obtained both in Europe and the USA. Illustrated with some 200 photographs and written by a master of diorama modelling with a lifetime's experience, this book provides the essential and invaluable guide to the materials and techniques needed to create top quality terrain for anywhere from Ancient Rome to the Western Front.
The Scenery Manual- The Scenery Manual is the complete Woodland Scenics guide to creating life-like terrain, landscaping and scenic details for your model railroad, military diorama or architectural model. For the beginner or for the advanced hobbyist this book describes the products, the tools, and the foolproof methods used in creating natural settings in scale. No detail has been overlooked. Contains all the proven advise and inside tips for achieving craftsman quality results the very first time. But most important The Scenery Manual offers the confidence necessary to begin any miniature modeling project and finish it with pride.