Once a week I give the indoor (warm weather) seedlings a good watering in the bathtub. The containers are filled with tepid water, and I leave the seedlings to soak it up for about an hour. I keep a spare empty flat handy, and transfer one flat of plants over to it, then dump the water from the now empty one and transfer the other flat of seedlings over to that. The smaller baskets have openings so the excess water can just be poured from them without removing the cups. This once a week watering seems to be just about the perfect timing, as the seedlings are looking quite robust. It won't be long before they will all be needing some up-potting.
I'm giving them some natural light after their soaking. The very slight breeze, 60 to 70 degree temperatures and dappled sunlight should make the little plants very happy.