Hey I have trouble growing it too. It seems to grow best I noticed in my compost bucket where I toss rotting garden scraps. To me this means it likes deep, fast draining, super nutrient rich soil to help it grow fast and strong. Super picky herb. I know it grows much easier in warm tropical climates, yet it prefers slight shade.

Good luck! Did you get yours to germinate outdoors? The photo looks like it is in a covered area. Let me know if you have any tips. I am about to try starting some lettuce seeds soon.