Is three of these sufficient for 2 plants?

[Nicky]

It’s all explained here, please give it a like if your learning.

Start using DLI

Daily Light Interval (DLI) is a quick and efficient way to calculate how much light our plants are receiving within a 24hr period, allowing for easy light adjustments. DLI will help you and the community to better understand your lighting in a more universal term, leading to clearer communication of what the true light value is. Almost all smartphones have the ability to use an app (we will get to this don’t jump the gun) in order to calculate DLI, and if that is not an option a cheap LUX meter…