With the warming temperatures, I have noticed that my trays have been drying out. Since having moist conditions is absolutely critical to germination of seeds and growth of seedlings. I have been watering my trays daily. To my delight, today I saw the first tiny, tiny seedlings in my trays.
Keeping the soil moist and warming up the trays ( greenhouse effect ) are some steps you could take to help your seedlings germinate.
Please send in pictures of your own seedlings if you see them!