Help with a dying plant please

[marko201177]

hi guys its my first post and also my first grow and its going wrong so i thought ill post here and see wot people think.
ill start by putting details of my set up ive got a grow tent 40x40x140 with a 250 watt cfl and a carbon filter and fan. im growing in my garage in the uk the temperatures are dropping now but average about 10 c outside so its about 15 c inside my tent maybe a little warmer. ive been growing 2 northern lights autos for 5 weeks on a cycle of 20/4 lighting potted in 50% compost and 50% top soil they where so well for the first 4 weeks the they started changing at the top the leaves where turning yellow and nothing was growing at all the last 3 days the bottom of plant leave were turning yellow also.
ive researched this and came to think it was a ph problem so i tested the ph and it was wot i thought above 7 so i done a flush 3 days ago on ph water i looked at them today and they dont seem any better i was going to do another flush but the soil is still moist and i didnt want to over water.
i might add i did add nutrients at about 4 weeks ive gave them it about 3 times im using biobizz grow but i havnt gave them any for week now. ill add some pics here also thanx in advance for any help marko.

 

[Xipp]

Your Plants will have a hard time fixing themselves with a in-tent temp of 15c or 59 degrees, That's way to cold your plants roots will not flush themselves or uptake nutes. Get some heat in your tent,Get the plants up off the floor if possible.Warm your nutes 68-75f. 20-23c try to keep your grow tent at or around 22c a little warmer would not hurt and seeing as how they are starving to death now FEED THEM. With a PH stable nute mixture...give them a couple of days and you should see some improvement..Good luck

 

[marko201177]

yh ive just done that mate ill have to try and get a small heater for the tent.thanks a lot for your help.