Now that they are germinated the don't have to be kept moist like they were when they were germinating. In fact keeping them wet is a sure way to invite trouble. Wait until they dry out a bit and then bottom water. I have a greenhouse so my watering is different than yours will be, but the basics are the same--wait until they dry out at LEAST half way and then bottom water. Others that have light set ups though say about every 3 to 4 days, but it depends on the size of the plant and the size of the pot. A pot needing water will be light. You'll see how much heavier it is after you water.

To bottom water--set the pots in a shallow dish that has water in it. Wait until the soil darkens a bit on top. Then remove the pots and let the excess water drip out. Now your plants are thououghly watered and can wait a good while before you do it again.

Letting a plant dry encourages the roots to go deep in search of moisture, so you have a better root system and a healthier plant. Over watered plants are week and have a poor root system, not to mention inviting diseases like damp off and root rot to set in.

I judge by the weight of the container. If it feels light (for its size) to me, it needs water. If it still feels heavy, then it doesn't.

Thank you both for replying. I'll make sure not to water till the tray feels light.

Julia

Julia you did not say, but I hope you removed your seedlings from the heat mat. It is tempting to leave them on the heat as they grow faster, but they do not make the best stems as they tend to be thin walled and weak. Al

Al: Yes, as soon as I saw the seeds germinate I removed them from the heat mat and took the dome off and placed the tray under the lights.
Thanks for responding.

Julia