I repotted today ( past due ). Roots were OK - just a tip if you ever try growing seedlings - don't use packing peanuts at the base of the pot. The milt roots went right through them and I had to cut the peanuts/roots off.
I took the opportunity to straighten them up in the pot/s. There are new growths starting everywhere - see photo.
I changed them into a medium bark mix with more sphag - say 60/40 mix. ( as an experiment, hope they do OK )
Ambient temps are about 63 - 68f. Still on a heat mat - so those temps may be higher for seedlings.
Humidity varies - above 50% to 62%
Lights on 11 hours per day. They do get a bit of natural light too.
Water now 2x per week.
Fertilise 1/4 dosage every 2nd-3rd watering
Smaller ones don't ever seem to catch up to the larger siblings.