Bubba Kush Seedling Struggling

"Not over watering, just keeping the soil around it moist." i think the other answers covered the possibilities of what's going on here... but this statement makes me a little concerned. you want to water a seedling in a similar way to any other pot of substrate... unless it is way too large you adjust slightly, but still same concepts. even at that size the tap root is surprisingly deep. root growth will follow the water... it is important to water at least a column of substrate (if huge pot) all the way down -- some runoff will ensure this has occured. don't keep surfact moist... that will only encourage a greater proportion of superficial roots. Erosion and other things will make these roots less useful that roots deeper down. This area evaporates the fastest and will have the most out of whack nutrient levels at any particular time because of that fact. allow surface to dry a bit ... with soil maybe 1" deep or a knuckle... then learn the weight of the pot at that point... the weight of the pot is the easiest and most consistent way to water at the same point in recurring process. never let "i do the same things to all plants" prevent you from observing and reacting to an individual plant. There are several environmental variables you do not control. There are genetics that vary. In general, less is more... this hobby has a lot of OCD nonsense baked in that does nothing but calm a neurotic need to 'do something' even when it is not needed. keep it simple... if you can't find it in a biology book or a proper source (not forums or this questions area) then you should be suspsect of the anecdotal knowledge... as much of that is often wrong. e.g. flushing at end of harvest to 'improve' the outcome is nonsense and an example of how if a group of people repeat something enough, even if wrong, many will follow and form faith-like beliefs in it. Some people tell you to cure in an airtight vessel... when anaerobic growth is the greatest risk to ruining a cure... turning it brown or bad smells like commercial/schwage weed that was left in a pile under a baking sun immediately after harvest. 80% of the information out there is bad. something you believe (and me too.. everyone) is wrong, almost guaranteed. so... don't form rigid beliefs... be willing to bend when facts contradict anecdotal nonsense. verify everything... don't just trust "me" (=anyone giving advice).