Droopy heads

my unknown variety/sex plants outside, keep drooping their heads every couple of days, any ideas please.

My plants droop when they are thirsty, how often are you watering? My plants would get droopy, I would water, and within 15 minutes they would perk up and reach for the lights.

every 3 days or so, I read that the plants like it dry so I have been frugal with the watering I always check at least 30cm in the soil for a dampness check