Seeds have germination but are not growing

[JamMakingWannaBe]

I have planted a variety of flower and vegetable seeds in 6 cell seed trays on my windowsill.

Most of them have germinated but they just don't seem to be "growing".

What should I do? They just have two tiny leaves so are too small to transplant. Could it be an issue with the compost I used?

How long since they came up? Are they getting g lots of light?

I have some antirrhinum doing exactly this, stubbornly refusing to add leaves. No idea why, usually they's be a fair size by now.

Seed leaves are quick to appear because they’re already largely formed in the seed. True leaves are more complicated and take longer. Plant is also growing a root system. See what it’s like this time next week.

My snapdragons have been like this since March, though.

I've grown seeds successfully on my window sills forever. This year mine are mostly pathetic. It's not a lack of light and the temperature in the house is the same as every year so no idea what's happened this year. I've now put every tiny little seedling outdoors and they haven't died but still not really doing much