What are your sprouts? The sprouts from tiny seeds, like nicotiana, can take a several weeks before I see true leaves. Keep the soil moist and cover off and try to be patient. After the first 3 or 4 sets of true leaves they grow much faster.

I was having the same problem. I was top watering the jugs. The dirt was too compact for anything to grow through. Check to see if the soil is too wet, or soil is too hard.