How do I grow thicker cat grass?

I've tried to grow cat grass a couple of times, and they always turn out so thin and never thicken, unlike the professionally grown ones I see in plant nurseries. It looks healthy to me but it's a bit awkward to manage, since they're so frail and tend bend down into a clumpy mass after just a bit of watering until it eventually dies.

Any advice on how to grow them thicker and stronger? I'm already suspecting not enough sunlight (was kept only in indirect light) and not enough watering (maybe? I misted them a couple of times a week). Last two photos are the specific seeds and soil I use. I used one pack of seeds for the attempt in the first two photos.