Hi, just joined your thread. Nice plants. I would like to give a little simplification of the led and heat. The Led is a diode (type of semiconductor) that has a junction between two types of material. It needs a certain voltage across it before it starts producing light. It also has a resistance in the material. The resistance just dissipates heat and does not add to the light being produced. As it is heated up the resistance increases. (such as copper wire, has a Positive Temperature Coefficient. "If a material exhibits a positive temperature coefficient means that as its temperature increased its resistance to current raises proportionately."
So the hotter the material, the more resistance it has. The greater the resistance the more power dissipated across it for a given current through it. So if you can keep it cooler there is less resistance and less power wasted just getting through the material. That is why they cool superconductors, to get the resistance down to nothing and the power doing all work with little waste. We are not in the range of superconductors but the cooler we run Leds the light output is a little greater than a hot led.
On inexpensive lights, I use screw in Led lights although I just used the light module and tossed the bulb bit and the screw in part.