I have a crop in vegg under t5 light I have ordered a led and was wondering if it is going to hurt my plants if I put under them for flower
What led You choose?
Which LED did you go with? Wattage?
You should be fine provided the LED is quality and provides your plants 2700K spectrum lighting.
I’ve done a couple of indoor grows now doing exactly what you’re proposing without any noticeable issues.