Sheila, Automatic AK

Hello @MissFlowerPower ! When watering in the early evening ( when lights are turn of ) the water has plenty of time to penetrate the soil for the plant to take it up but the leaves might stay dump overnight and that can cause problems with fungus . Watering in the morning ( when lights turn on ) lets the leaves dry out faster so you can avoid fungus problems but there is less time for the water to penetrate the soil and for the plants to take it up before the temperature gets hot ( That's the case for outdoor growing and two reasons for that. First reason when temperature gets too hot the water will evaporate from the soil and second reason when temperature gets too hot and plant loosing water at high rates by transpiration the guardian cells close the stomata so no water in form of vapor goes out from the stomata and no water goes in from the roots but that's happening when having very hot temperatures, like direct summer sun light ). Also watering when lights turn on will help the plant to deal with high temperatures and regulate their temperature by transpiration ( until the point that temperature gets too hot as i explained above ). Plants use the precious hydrogen molecule that they need for co2 fixation to sugars from previous waterings and not instantly. So in conclusion it depends from various things but in general when growing in a indoor controlled environment its best to water when lights turn on. But the most important thing for the plant is to have a watering routine. No matter when you decide to do the watering try to do it every time the same time. Happy growing ! 👊