Urgent help needed - Leaf curling, yellowing and spotting.

What is wrong with the plant in this picture? The problem for now seems to be on just one leaf but I've already lost another plant with the same problem. If you can help me solve this without flushing (compost can't really be flushed since it dries slow as hell) I'll be eternally grateful

So here is some info regarding the plant:
Age: 5 weeks and 1 day
Symptoms: Leaf edges curl downward and the leaf starts to dry. There is also yellowing and some brownish yellow spots on the leaves.
Medium: Own mix of about 2 parts compost to 1 part expanded clay pellets
Nutes: Miracle-Gro Ericaceous Plant Food 30-10-10
Dosage: 1.25ml per 1.25 litres of water
Water: Mineral bottled water and dehumidifier water corrected to a ph of about 5.9-6.2
Water schedule: approximately once every 2-3 days and misting once or twice every 1-2 days

Looks like it could be a lower leaf that isn't getting alot of light. It could be nute splash.....

So if you water a plant and some water stays pooled on a leaf the nutes will burn the plant? Coz that happens to me all the time and I just leave it there

Yes........

Also, if your almost 6 weeks you should either take the lower branches as clones or remove them to focus growth on tops and increase air cir...

Should I also prune the plant if I'm doing LST?

And here is an updated picture of how it is right now, it got worse so I splashed some water on it and cranked the muffin fan to top speed.

It's wilted like hell by now I don't want to lose my last plant, anything that can revive it quickly?

Losing her fast here.. anything?

Still worsening.. I need some fast help

Im on my first grow atm so Im a total noob..but dude, that plant is gonna die

Ye it's my first grow too. And it's just the leaves that get fucked up, the stem stays strong and healthy, it really pisses me off and I'm sure that there's something that can be done since it's wilting quick, so it looks like it's just a problem that can be fixed.

edit: K I just misted the plant with distilled water, if by tonight it's not looking better I'll throw in a humidity dome so maybe it'll keep some moisture in and stop wilting and drying.

first off the plant is gone, rip it up and start over. secondly, what is ur light source. looks like cfl's from the pic but cant tell. how often are you using nutes, everytime u water or what? Don't use MG fertilizer, go to ur hydro store and buy some foxfarms nutes, if u dont have a hydro store order them online but ship the mto a buddies house. those are the best imo. i use the grow, the bloom, and the bat guano with good results.

Yes I was using them every watering, is that what the problem is? And yes I'm using CFLs, so there's absolutely no chance of getting that plant back to health? It's not completely dead yet..

I just think I saw a couple of whiteflies on my plant :/ I'm suspecting that could be the problem

You are making a lot of mistakes there man. Splashing water on them will burn them too....unless you are using a wetting agent. The drops of water form little magnifying glasses on your leaves and you'll get spots that way too. You don't need to give nutes every feeding either...you will get a major nutrient build-up of salts in your soil. Get a flushing agent and flush them. Do a feed flush feed schedule, or a feed feed flush. Its not past the point of no return...but it will take a good while for it resume normal growth. You need more lighting. You can use MG, but I would use something else. Testing your run-off ppm and ph will provide loads of info about what is wrong. And get some sticky paper to catch the flies...or something that is made to get rid off them. Hope I helped some

Happy to report that a humidity dome and a hell of a lot of misting (until I got the top of the soil wet) got us perking back up

I don't think if it was whiteflies shenagen, unless they can be killed by water, coz I started misting like crazy and firing at them with the mist bottle and they seem to be gone.

Thanks everyone for the input