hi, clearly the watering has not helped, so we can rule out it been under watered or even over watered if the pot was nearly dry when you watered,
try and get a temp and humid gauge so we can see what your working with,
the soil you have bought should easily feed the plants for 2 weeks in a small started pot and another 2 weeks after transplanting, thats with most compost/soil mixes you buy, some can be to hot lie miracle grow and im sure ive read fox farms can be to hot on its own so needs mixing with perlite but i cant comment much as ive not tried it,
if the soil had way to much nutrients in it then the leaf burn would of carried on, but it hasnt and your just getting droopy leaves, we have ruled out water been the problem, to me the leaves look a bit on the light side, if the soil you bought was for starting seedling then it might not have much nutrient in it how ever it should easily feed the plants for 2 or 3 weeks,
let us know how tall the pot is and what the width is across the top, so is it 1ft high and 1ft across from side to side for example,
give us these measurement then we can check if the plants are having root issues or used up all the nutes,
with the nutes you have bought you need to only go with 1/4 stated dose of even a 5th of the stated dose, so if it says 20ml per gallon then add 5 or less, with the nutes i use the first feed is just 2.5ml per gallon, but as the plant get bigger the feed schedule increases to around 20ml per gallon, so you need to start on the low side and see how the plant reacts, you wont see any difference for a good few hours.
now it does look like you had nute burn to start with which would suggest the nutes was to high in the soil, but as this has not progressed then this suggests either the nute level has dropped or your having a lockout problem caused by incorrect ph of the soil.
we just dont know whats in your soil or how hot it is, so let us know the pot size, the date you planted the plant or rough date if your unsure, dont add more water or nutes at this stage, if the soil is low on nutes then you will see a difference in the next 12 hours after adding nutes, the leaves will go a darker shade of green if the plant is just low on nutes.
to me it looks like a plant that had problems early on but then recovered, but the wilting leaves suggests their is something else going on, such as temps or root issues, but the plant is still young and ive seen much worse so its not as bad as some plants and should do ok as it gets bigger,
you dont have a fan blowing directly on the plant do you, at this stage a fan blowing on the plant will just dry the leaves out and this will make them wilt, you only want a gentle breeze so if your using a fan direct it on one of the walls so it blows around the room and its then not blowing as strong on the plant.