Grow light marketing leans heavily on spectrum charts and specialized terminology that mostly does not matter for the average home gardener starting seedlings. Here is what actually affects seedling growth.
"Full-spectrum" is mostly a marketing term for seedlings specifically
Full-spectrum lights aim to mimic natural daylight across the visible range, which matters more for flowering and fruiting plants than for young seedlings, whose main need is simply enough blue-heavy light to prevent legginess. A basic daylight-temperature LED shop light will grow healthy seedlings just as well as a marketed "full-spectrum grow light" at a fraction of the cost.
The number that actually matters: distance and intensity
Seedlings grown 12 or more inches from a standard LED shop light almost always stretch and become leggy, regardless of how the light is marketed. The fix is proximity, not a more expensive light — keep seedlings within 2 to 4 inches of the light source and raise the light as they grow.
Duration matters more than intensity
Fourteen to sixteen hours of light daily produces stockier, healthier seedlings than a brighter light run for a shorter period. A simple outlet timer is a better investment than upgrading light intensity.
When full-spectrum genuinely earns its higher price
If you are growing plants to flowering or fruiting entirely indoors under lights — not just starting seedlings for later transplant outdoors — full-spectrum lighting does provide a real, measurable benefit at that later growth stage.
