Isn't looking too great, I don't want to repeat

This is my first attempt at growing. When the seeds sprouted i wasnt too prepared and that caused them some stretching in the earlier days but then i got some lights above them and everything was looking great. No drooping, all the leaves looked a healthy green. I started fertilizing about a week and a half maybe 2 weeks after they sprouted with half strenght miracle grow all purpose 24-8-16. i think the second time i fertilized was a week after the first time i fertilized then i watered twice with just water. Then 2-3 days later i go to fert them again and i notice that the bottom leaves are getting a yellow color and it doesnt look nice. So i look around on the internet and from what i read it looks like some sort of nutrient defeciency. I didnt want to feed the plants until i measured my ph but didnt find the ph test strips. I watered the plants with about full strength fert a good amount at that. The next day i find the strips and measure the water i have been feeding my plants and nothing seems out of the ordinary. The yellowing keeps getting worse until the bottom sets of leaves die on both plants, then the brown tip and yellowing start to move up to the next set. 2 1/2 days after i feed the plants i panic and again feed them with full strength. a day or 2 later i see the drooping which i believe it because of the overwatering and i haven't watered since. so last time i feed them was with full strength 3 nights ago. The yellowing has hit up the second set of leaves pretty hard and has started to move onto the next set. This is frustrating the hell out of me. I want to know if i can save these plants at all or even clone them. I already have a couple seeds just finishing germinating and am going to plant them tonite. I want to know where i messed up so this doesn't happen on my second attempt. The soil im using is Vigoro moisture plus (0.02-0.03-0.02). Is this soil any good and if not could u please recommend some that i could find easily. I think my room might have been a lil dry and a lil hot but i dont think too much ill get some readings soon. Thanks, i hope i can get these pics on.

 

For the half strength i was using 1/8 teaspoon for 2L then full i used bout 1/4 for 2L. If it's fert burn why is it starting at the bottom and moving up? I'm not doubting you or showing disrespect i was just under the impression that fert burn would show up on all areas

 

It only started drooping recently after i overwatered it twice 2 days apart. But the yellow leaves is just fert burn? and i should add hydrogen peroxide to my water for flushin? thats the stuff that you put on cuts to keep them from being infected right? and for how much i watered them i think it was prolly 150ml ea. 2 days apart maybe a little more. Why is the yellowing moving from the bottom up?

 

Alright i just added a small amount of hydrogen peroxide and watered both with not too much water. How long should i use the water with hydrogen peroxide? Should i not go back to fertilizing for a couple weeks?

 

k thanks 4 help all. Now i guess i'm just going to wait and see what happens these 2 were kind of ment as a learning thing so im not to choked. They don't look very good at all right now very droopy. by the way gurella sorry for the misunderstanding i didn't think it was the overwatering turning the leaves yellow, i thought it was only causing the drooping, my bad. Anyways thanks for the help and ill b sure to update soon. They don't look very good tho might not have anything to report but lets hope not. any more advice appreciated thanks
P.S. Also another question. When i start to feed the plants with fertilizer should i b starting with a small strength, watering it every water with it and slowly moving up the strength? or should i have a scheduale of watering clean then watering with fert again with small strength moving up? or wat?