Seedling leaves turning white, no true leaves

You can overwater in any substrate. One with good drainage and aeration is just more difficult to do so. This does look like it's been too wet for too long. You can easily eliminate this possibility with a reflection on behaviour.. if doting too much and not letting it drink down at least some portion of water-weight in the pot before irrigating, it's probabaly overwatering. It's just as hard to overwater in 50/50 sphagnum peat moss + perlite as it is in 70/30 coco+perlite, because it amounts to the same water:gas per volume in the substrate, which is what matters.. no the material absorbing the water, though those properties are important for how much perlite or similar to add. the 50/50 and 70/30 recommendations are due to these differences in water retention. it's common when you start to grow to try to do too much. Right now you just make sure it doesn't dry out and let it do it's thing. The first 7-10 days is slow.. even that first set of leaves doesn't speed things up too much... But it gets faster each day. Soilless SOP is easy once it's not a delicate seedling. 1.3-1.5EC fertigation every time with 10% runoff and don't let it sit in its piss. Easy-peasy. Adjust formula based on observations of plant. keep some notes to reflect on.. fertlization is about all that you've done and not just what you did most recently. Frequent fertigation isn't for seedlings or small plants. You still need at least 33% of the water-weight to be drunk before re-fertigating. if the plant size and pot size doesn't jive with that intention, you can't force it to happen. This is only useful after a plant has a robust root system.. doing it early will only reduce root mass by comparison to a healthier wet-dry cycle. i don't think this will die, it looks okay. If you don't get any vertical separation between the cotyledons and the new set of leaves, back the light off a bit. You may need to increase the power later, but early it needs a bit less... allow the length of stem between growth nodes (internode) help guide light power. take some notes, so next time you have a good plan to ramp up and not have to react to the plant as much as you deliver on demand. this is always a l ittle different due to local variables. so it's a necessary trial and error process. fc 4800? 65-70% at 18-20" is probably full power on an 18/6 cycle, give or take. this may be too much for a seedling, but within a week or so, it should want more... if it got stunted at all, give less light for a bit and it'll snap out of it. The stretch/tightness of nodes is the guide. TDS pens are useful, but calculating your nutreint ppm per element is much more accurate. this is what should add up to 650-750 ppm, give or take. Even 600ppm can work well. PPMs - a good starting point tha tmay need adjustment but any symptoms will be easily diagnosed and slowly progressing... 120-130N 60P 180-200K 100+ Ca (this depends on tap water. e.g. my hard water adds a bit, you may need more than me) 75Mg (see Ca, same reasons this may vary more than others) 100+ S any good hydro/soilless nute system should be pH stable/buffered and provide all the required trace elements too. There are online calculators and phone apps that you can type the percents off your guaranteed analysis labels of your fertilizers, enter in dose and it'll spit out a tabulated total of each. Easy-peasy. Way more accurate than a TDS meter.

I see leaves growing.. it's slow to watch that first 7-10 days. It's a exponential curve at this point, though. So, trust it will happen. Don't fiddle. Keep it simple. Overwatering issues is possible in coco. it is not a magical substance, lol. This does look like the roots are too wet for too long. You can easily refelct on your behaviour and determine if this is true.. have you been doting excessively? spraying every do or otherwise fucking with it for no reason? :P it's understandable if new to it. Most have felt the same anxiety/motivations. While seedlings may need to avoid the top layer drying, it's a good practice to adhere to in vegetative phase for sure. promotes healther, more robust root system. A good wet-dry cycle in substrate promotes deeper roots. you don't want to promote superficial roots, as they are less useful in the long run. any exposed to light will tern to stem.. i.e. wasted growth. It also avoids microbial growth on your top soil. It's usually not a major issue, but it is a disease vector if you have some bad luck. Soilless growing is very simple stuff. you can fertilize day 1 with 1.3-1.5 full strength, but it's not entirely necessary. The seed has enough for 7-10 days. when i use coco i typically get it wet with heavy runoff at a specific pH. Let it drip for 10-15mins then go sow some seed. Experience with your seedling pots help here. I know with a humidity dome, i don't have to worry about watering my little 2.5" seedling pots for 4 days or more. That first irrigation i will pre-empt any drying on top layer, but I also make sure the weight of the pots has dropped a good chunk before irrigating. If it's still heavy, it still has a tone of moisture and no need to irrigate. Always 10% runoff or more.. always. Never let it sit in its piss, either. After that it's SOP... Wait for top layer to start to change color and fertigate with 10% runoff. 1.3-1.5EC well-balanced formula (not including what you water from tap adds - can most accurately calculate this from guarnateed analysis labels and find an online ppm calculator or phone app to do the math for you and add it up) 120-130N 60P 180-200K 100+ Ca (this will vary, i have hard water, so i get some Ca from the tap, for example) 75 Mg (again, will vary based on tap water) 100+ S That's maybe 1.2EC? TDS pens are meh. Trust the math from the labels, as that is most accurate way to measure this stuff for soilless/hydro context. I use plain ph'd water to start because it gives a natural ramp up for the fertilizer and i don't have to mix it at different concentrations. this 'first' fertigation after planting will be some portion less than 100% as it adds to what moisture remains in the pot and bsasically 100% by 2nd fertigation. the 10% or more runoff quickens the pace. Even at full strength this is far lower concentration than you find in any potting soil, so it will not harm the seedling. Later on if you want to gas it for flower development, frequent fertigation is possible with any soilless substrate with proper drainage and aeration qualities as well as a plant that can drink down at least 25-33% of the water before you fertigate again. the weight of the pot will be the best indicator for this. If these things don't jive well and you try to force the fertigation frequency, it's just flipping a coin to run into trouble. Keep it simple.. patience, grasshopper.. If somewhere near the above SOP, it's probably fine.. make any adjustments and move on.

Some seeds don't make it. I've had this done on one of my grows, the plant will grow it just might take an extra week or so. I had theories on why this happened but nothing solid. I also think that it is overwatered, seedlings don't need water everyday they are just starting out. it can also help them to have more perlite worked into the soil where they are planted but leave the rest of the pot as is, extra perlite helps with aeration and prevent saturated root issues in short term of it getting established. Everyone has their own grow method so their will be some conflicting information. I also think if your growing in a medium like coir, that is void of nutrients will require a small feeding IMO. Around 100ppm kinda thing, very mild. If your coir is not buffered or from a lesser brand it will also need a rinse and some CaMg before you plant, off brand coir can have a EC as high as 2 as they use salt water in the processing and all the salt stays in the coir. I'm a big fan of CANNA branded coir products. rinse, buffered and aged/fermented. Good Luck!

Coco is suppose to stay wet always, just not left sitting in run . So water is not the issue. The issue I see is you started feeding too early. They don't need feed till day 7. Just 5.8 ph water. Which is also another part if your issues I believe. Coco is very ph sensitive and high irrigation. So lots of run off, and ph checks of that run off. Vegging should be 5.8 in 5.8 out in run off.

Yes you are probably watering a bit to much,keep them just a bit moist but not really wet the first days,I stay about 3-5 cm away from to plant when I water so the roots need to go searching for the water,this way you develop a strong first root growth and your ladies start growing strong immediately 💪🏻 Happy growing 🌱💪🏻✌️