Hi orbaughb,
I have never had to water them. But we get quite a bit of rain in the winter and spring here in the PNW. If you haven't had rain once the seeds germinate you can open the lid and check the soil. If you have to water just use a garden nozzle that will put out a spray, water with the lids closed, so you don't disturb the seedlings/seed.
I do wet the soil when I plant the seed.
If the weather has warmed and I am not ready to plant them out, I cut the top off. They are usually only without the top for a week. At that time I may have to water them if there is no rain.
The tops can also be used like mini green houses to cover the newly planted seedlings if there is threat of frost. It also protects the young seedlings from deer, squirrels and other pests until they get going.