Milled spaghnum has been shredded, sometimes ground. Better brands (especially in seed starter mixes) have been pH ballanced & stabilized. I don't care for coco. Bad experience with the one I got having enough salt to KILL. If you've found one you like, DONT CHANGE BRANDS, or you may wind up repeating my experience. Peat pots are bad because they loose that pH stability, cheaper stabilization process.
---- You had nute burn. Fox Farms ocean forest too rich for seedlings. I love it. Its what I transplant into about a week before 12/12, but I still cut it a little. 3 pts ocean forest, 1 pt pro-mix organic. Love pro-mix organic, but nutes aren't long lasting enough to see you through to the end. Only about 1/2 way. I use pro-mix standard as a seed starter for all plants, veg & floweres too. Mostly milled spagnum & perlite, no nutes, so no seedling burn. I start my seedlings off by watering with fish tank water, but it MUST be from an untreated tank. No meds or salt. I like the fact that there's low, non burning nutes & TRACE ELEMENTS here, but mostly growth hormones that encourage femininity. Gold fish (no tropicals) make the best tank water. If u have no fish, then I use Fox Farm Big Bloom diluted to 1/4 strength. Do either till seedlings are big enough to take nutes. Big Bloom seems to have the same growth hormones as tank water to encourage femininity, & that makes sense, since it also has sea bird guano in the formulation, & they eat fish.
---- Pro-mix is a nursery product that usually DOESN'T cater to what we grow, & you actually need a nute free seed starter because seedling roots can't actuall take it up at first, & they burn so easily. Thats why I use & recommend the pro-mix standard. And what I highly recommend to start them off good & healthy is the fox farm Big Bloom. Thats carried wherever ocean forest is carried. As soon as I get off my lazy ass & get some work done around here, I'll be posting more detail about this on my camper closet grow. Probably next week. Damned! This reads like a sales pitch! LOL! But I'm passionate about products I love. ~~~ PEACE! ~~~