Some take to greens easier than others. My first beardie wouldn't have anything to do with them until he was about 9 months old or so, but I've got a pair of 3-month olds right now that ravished them the first time they tried them. These are the first ones I've ever seen tear into them like they do.
First of all, offereing as much of a variety greens, veggies, fruits, at one time as you can helps. Another thing that's helped me in the past is to mix some worms in with their greens. The worms' movements get their attention and they'll usually get a piece or two of greens while grabbing a worm.
I'll usually feed the dragon crickets in the morning and place the greens in the cage soon afterwards. I leave it in the cage throughout the day in case they get hungry for a snack. Put the greens on the cool side, so they don't get dried out too fast. With a few worms mixed in the dragon will eventually acquire a taste for the greens.
Patience & persistence is important. Give them greens every day, whtether they touch them or not. They eventually will. Some will eat more than others. My adult male will put away half a dish full at one sitting one day and not touch any reens the next day.
Take care!
HH
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Due to political correctness run amuck,
this ol' hillbilly is now referred to as an:
Appalachian American