Granular garden cote 6 by fertiloam works great on these guys. just sprinkle on the surface of the soil. I've got one that i''m growing but just watching it this year. The pot you have it in is plenty big for at least a couple of years. surprisingly these little guys tolerate. . . wait for it. . . .FULL SUN. without even blinking in fact they love it. They will start to grow smaller leaves and more compact foliage. Do some reading on caring for other maples the care is very similar to other varieties, the trident is a very close cousin and have similar feeding and watering requirements.