Not to hijack the thread, but I'm also in the desert and have some seedlings in cups (inside now).
I was told that I'm over-watering but it appears they grow better with the soil constantly moist, and in my experience with other plants this seems to be the case.
With how dry it is here I've been watering them about once a day.
Is this not the correct way to do this?
Their not sitting in standing water.