Meh, what a week. It rained until Thursday, I though about buying an additional lamp to get some more light hours to the plant. But the sun came out for the weekend and the plant finally was able to grow a bit more!
Could it be possible that you put the seed with the white root to the top into the ground? you got to put the root into the bottom direction and the seed to the top and don't put them to deep into the soil.