My lemon has yellow leaves
I have brought my Meyer lemon in and put it under a grow light about 8 inches above and have left it on for 4 days. The leaves are starting to turn yellow now. Does it need some dark time?
Yes, you should use a timer on a grow light system so the tree has enough light but not to much.
Your Meyer Lemon Tree needs 8 to 12 hours of sunlight to be healthy. If your home can provide 5 hours of South facing sun, they add an additional 5 hours of a grow light.
Here is a link to refresh you on the care requirements.