I think you are watering the plants with a little amount of water very often, daily or every couple of days. You should be watering the soil fairly well one time, allowing the soil to dry out (about a week or more after fresh transplant) and then watering again. For fresh transplants I water about 1/4th the amount of dirt in water, or a little less because I want the soil to have a lot of oxygen. After they dry out from the first watering I thoroughly water until a good amount of water drips out of the bottom (unless you are organic soil water only, if so follow those rules).. But if you add nutrients you do want some runoff when you water. Over time the days will decrease, quickly at first from 7 days to 5 days to 3 days then when it's around 1 or 2 days your planter is too small.
First I'm assuming this is stress from watering too frequently but also not watering enough when you water can also show the same signs. So if you let them dry out and they worsen then water thoroughly as I described above. If it is watering too frequently, my guess, then to correct your problem we have to be precise. You need the soil to dry out fairly well before we water again, but there's not a lot of water in there so it gets risky. When the soil is fairly dry again then you should thoroughly water them and again we expect not to be watering them again for a week. (pickup the planter daily to see if it needs water though)
Lastly you never want to water frequently around your stem that can cause dampening off. Also your plants will be growing roots for awhile, about a week or so and they won't be using very intense light. Watch out for light stress, technically that drooping could also be light stress.
