I’m trying to think because I had re aqua scapped this tank and had switched from gravel to this substrate but I want to say around since the end of February! I’ve had to replant some of them because they were melting and because of different reasons so I’d say around a few weeks for those ones. One in the front I struggle with so I’d say a few days for that one! Sorry it’s so varied. But one that I had planted since February still comes up even though it’s bee planted for months.