Im just starting with live plants with just a couple of hornwort in the substrate but wanting to go for a lot more plants!
Then look for decent "plant" light, as AbbeysDad rightly pointed out, you are best with a "natural daylight" spectrum. You can fuss over various technical issues, but I have never found it necessary to go much beyond spectrum which is expressed in Kelvin, and light that is natural daylight will have a Kelvin rating in the range of 5000K to 6700K. A higher number means much less red and much more blue for a much "cooler" white, while lower numbers are more red and less blue for a "warmer" white. Unfortunately, words are useless here because they can mean different things depending who uses them, so it is the Kelvin number on the package/tube/fixture you need to use. But even then not all "6500K" is the same, I have discovered.
Intensity is a very different distinct issue, regardless of the Kelvin. So "X" manufacturer's 6500K LED unit might be very different intensity from "Y" manufacturers 6500K unit, not to mention the colour may be different too. I can't help beyond this as I have had no real success with LED and still use T8 fluorescent which I do understand and with which I have had tremendous success, but my tanks are fairly low-tech and I don't try to grow difficult plants.
The colour I should mention about, this is critical for plants because aquatic plants need red and blue to drive photosynthesis--remember, the intensity enters this too--but if there is not sufficient red especially, photosynthesis is slowed and can be stopped. This is why almost all the non-plant LEDs fail, they are much too "cool" (high blue) with very low red in the mix making up the "white" light. BTW, "white" light is of course a mix of several colours, and mid-day sun is the aim, which not surprisingly is best achieved in the 5000K to 6500K range.
