PAR readings and your lettuce
for those familiar with PAR and are using it to measure their lighting system, I have a question..
According to an article, lettuce needs around 14-17 umol-m-d-1 or a daily light integral of 14-17.
Additionally, a 70watt metal halide could produce 1550 ppt at 1 feet distance according to another article.
Going by those numbers, am I missing something If I concluded that lettuce needs only around 3 hours of lighting under 70watt metal halide to achieve a daily light integral of ~16?