PaulliesBuddies

Its hard to determine but you should be safe at 60 cm. LED's vary in how bright they are. You would have to let us know what brand/model you are referring to. Is it 300 true watts( pulls 300w from the wall). Is it a cob light or burple ( blue/purple ) light, quantum board. Just a warning, I would not have more then one plant in the same pot at a time. The will compete and bring each other down. A lot of energy will be wasted fighting for root space and light. I would either separate them or select the strongest and kill off the weaker one.

Anywhere between 30cm and 60cm to be safe you can experiment though a hanging guide should of been with the light though there are more guides online you can follow. I think bar lights can go alot lower but i think thats a different story it all goes on what you light you have if the diodes are really powerful even a 300 whatt can harm a seedling I know first hand my telos 0010 pro cannot grow seedlings at a low hang height the 2.5 umol leds are just too bright and that unit is only 285 whatts i think you just gottta experiment yourself :)