Waterproof is very important for LED grow light. LED MODULE TOPIC. Solder paste is used to solder the LED on the PCB. In the previous article, it was mentioned that in the environment where plants grow, humidity RH85 will be encountered. Moisture will cause the solder paste to oxidize within one or two years, which will cause the LED to fail bright. Therefore, special glue is required to block the gap between the LED and the PCB.