its normal for beardies under 1 year to neglect their salad, mine is several months old and rarely eats her salad. when they get older they will need to eat mainly salad. you can try to intice your beardie by spraying water on the salad and moving it because they like things that move. if your set on feeding him more salad you can cut back on his insects, but this is not advised because your beardie is so young. I would just keep the salad in there everyday but still feed him his insects and wait for him to get older before weening him of insects. also you can get a product called jurassifriut, strawberry or banana, it has a powerful fruit smell that atracts your beardies nose to the salad.