You may worry about the drop in LED working efficiency when the temperature gets high. But you don't have to, if your LED grow lights use quality PCBs that can dissipate thermal quickly.
Most of the LED grow lights PCBs are aluminum-based. Aluminum PCBs from PCBHERO have a thermal conductivity of 1W/mK to 9W/mK. This thermal conductivity is enough for the needs of most LED grow lights.
However, if you want a better thermal conductivity of the LED grow lights, you can also choose ceramic PCBs for your design. Without a dielectric layer, ceramic PCBs have better thermal dissipation than aluminum PCBs.
Besides aluminum PCBs and ceramic PCBs, from PCBHERO, FR4, copper, and glass substrate PCBs are also available for LED grow lights.