4/5 Seedlings have not sprouted after 1 week

Some take longer. I've seen 2 days, i've seen 7-8.. and that's limited experience... so longer is assuredly possible. google to double check, but i think 14+ days or more is when they are likely to begin to rot? i'd give it 3 weeks to be safe - what's the harm? while you want some dry-wet cycle later on, you want the substrate moist, not sopping wet, all the time before sprout. that one looks a tad dry. another looks like it could only be superficially wet. Make sure to have a little drainage, then don't water for likely 2-3 or even 5 days later. environment will play a big role with rate of evaporation. Don't fertilize beyond initial buffering of coco. if you do, ensure ~20% runoff. rehydration the first couple weeks is all it'll need though. Seeds are packed with energy. cotyledons slightly fade = ferts. in future jump the gun based on time you typically see. in coco you may not let it dry as much as soil, but it is good stress for root growth. i don't wait for top layer to dry of my coco, but i do try to have an ebb and flow of some sort as a preventative measure to keep microbial growth in check and ensure oxygenation at the roots etc. so, you don't want a planted seed dry at all and you don't want it sitting in sopping wet soil for long periods of time... it's much easier once you have familiarirty.. if like me, you just want to do "something" early on... but, better to water and forget until effort is required, not because we feel the need to do anything. I've been soaking my seeds until they sink, then planting. At the least, you ensure it's fully saturated and it should cause it to germinate. I don't like touching or otherwise fiddling with a seed that has germinate.. touching the root, expsoing it to light are bad things. but, might shorten up this period especially for older seeds from what i've read.