Leaves are yellowing! please help.

[ÕceanGrÖwn1]

OK, so my set up is as follows.
-mylar tent 1.2 x 1.2 x 2.0 meters, 1000w MH adjustable ballast, 420cfm exhaust fan, 420cfm intake fan, etc...

I have no idea whether the problem is under/over nutrients or environmental.
It all started about a week ago when I decided to seal up the three flaps on the tent that were constantly open. Temps were getting too high and the exhaust fan worked twice as hard sucking in warm room air. Would 420cfm intake/exhaust be too fast and cause the plant to get no oxygen??

Also gave the 5 week old plant(critical+ strain) her second batch of nutrients at approx 800ppm. Im certain she has NOT been over watered(made that mistake on my first grow). Im thinking it may be a deficiency of some sort, as ive been going very easy with nuts this time around(slight burn on first grow again lol). Maybe magnesium as she hasn't grown at all in 7days!? Soils ph is fine and the light was adjusted from 500w to 1000w over 4weeks...

 

[Hash Zeppelin]

sorry bro your pics dont work.

 

[ÕceanGrÖwn1]

They worked fine on 420mag? Just couldnt get a decent reply. One more shot.

 

[Hash Zeppelin]

cal/mag. the spots are calcium, the yellow is magnesium. also add some carbohydrates, and re balance ph. also soil looks pretty dry. do you till the top soil after water, and once a day in between watering? also it looks like you need to transplant into bigger pots soon.

good luck

 

[ÕceanGrÖwn1]

Carbohydrates for plants? is that different to general vegetative nuts(using canna 14-06-10)? I havent tilled the soil just in case I damaged the roots. mind explaining a little about it/how to do? transplanting next week if all goes well

Also, can i give her the missing nutrients now. soil is still moist from a straight ph'd water 3 days ago. she isnt drinking it as fast as before the yellowing..

 

[cannaera]

use mollases for carbs. sugar feeds your microbes which break down the nutes to feed the plant. you should also try a feeding of 1/4tsp per gal of epsom salts or foliar spray epsom salts at a slightly higher dosage.

 

[RetroGrow]

The real yellow leaves on the bottom mean nothing. They are not getting any light and the plant doesn't need them anymore. Completely normal for bottom leaves to drop.

 

[Crooked8]

They have nitrogen and cal deficiency imo...

 

[ÕceanGrÖwn1]

Thanks for the advice guys, not so worried anymore! I gave her a decent dose of canna veg and tilled the soil afterwards. Rock solid in places so im thinking that was a big factor, cheers for that Hash Zeppelin.
Ill update pics in a few days. peace.