I'm also interested in hearing responses! If you don't have anything rigged by the time you have to leave for your first trip, I've heard covering your plants with a plastic bag can be a good way to keep the humidity up if you can't water. In that case you might want to skip the lights for those days so they don't overheat in the plastic.

If it's no more than a week away from home at a time, I'd just set up a timer for the lights )16 hours/on - 8 hours/off).

I wouldn't worry about watering -- I would just make sure that the soil was moist before departure. Most seed starting mixes provide enough water retention for at least a week for young seedlings. When it gets to be less than that, it's time to pot up anyway.....JMO.

I would also check for aphids and such before leaving and maybe spray once a week with some neem oil just to put my mind at ease while away.

Might also pull the lights away from the tops another half inch to prevent growth hitting the lights and burning foliage.

Good luck.

Kevin

TWO days is a very short time as far as watering is concerned. I practice "bottom" watering , once a week or so. To have some moisture, you can place them on gravel, in the tray and add water to it.(Below the bottom of pots)

With the lights, as Kevin already mention, get a timer and program it.

What size pots are your plants in?

WHAT SIZE POT ?

I have mine in 2 1/2" square or 3" round. For couple of months. At the transplant time the pots are half full. As they grow bigger( slightly taller than the pot, I refill the pot , leaving about 1/2" Then I fill that 1/2 space with small pine barks.
This way, I don't have to water them too frequently . Also the roots can grow more freely.

I am planning to do small Styrofoam coffee cups.

I rigged up a bench with a shop light and a plastic cover this morning. If I can make it to town to pick up some seed starter soil mix, I will plant seeds tonight.