I'd recommend especially with a granular, non-cannabis-specific plant food that you schedule a HEAVY watering with plain pH correct water about every 2 weeks to flush out the stuff the plants didn't use from the previous feedings. I've used that same product to grow pot in the past and it's fine but you gotta watch out for overfertilization and salt buildup.
Just a heads up. But Rusty's got you going in the right direction!