big bang bottom fan leaves yellow and dying

[mcon]

big bang auto with lower fan leaves yellowing and dying off.

experience level. first timer

Equipment:
.1) 250 watt dual spec sunmaster hps
.2) Distance from tops? 18 inches
.3) Reflector type? maxibright dutch barn reflector
.4) consistent fresh air supply? 12 inch passive intake
.5) exhaust fan and a circulation fan? 100mm systemair rvk extractor, 2 x 7 inch oscilating fans

medium:
biobizz all mix
3.5 litre air pot

nutrients and water:
tap water, starting ph 7.5 sits out min 24 hours and ph'd to 6.5 using distilled vinegar.
bio bizz grow (4-3-6) and fish mix (6-2-4) 1ml of each per litre (rough watering volume is about 600ml every 2 - 3 days
ph in 6.5, ph out 6.2 -6.4

Indoors
W 2ft x L 2ft x H 8ft airing cupboard with extraction directly outside
temps high 81 low 71, 48 - 50% humidity
no insects

strain:
greenhouse seeds big bang auto fem, 3 weeks old


desperately need help here. looking up it looked like N def but i'm just not sure and wanna get expert advice before making a move. i have read that when using air pots you have to increase nute levels as so many nutes leech out during watering, but dont quote me on that cos theres so much mis information flying about that i really dunno what to believe.

any help appreciated dudes and dudettes.

 

[KindredSpirit]

Hey mcon. :smokebuds:

The even yellowing looks to me like it's an N deficiency. It sounds like your soil pH is pretty close to on point based on your runoff numbers, although a runoff of 6.2 when 6.5 is going in means that your soil pH is down around 5.9 - 6.0 which might be a little low. I'm not familiar with the Bio Bizz nute line, so I can't really speak to whether or not you should up your feeding level, but it looks to me like she's hungry. If you're already giving her the recommended dosage, maybe a foliar feed might be in order. Hopefully someone who is familiar with the Bio Bizz lineup will be through shortly bro. Don't panic, we'll get ya sorted out.

:smokebuds:

 

[mcon]

Thanks for that brother. That has made me feel a bit better. I've never done foliar feeding before would I do that in conjunction with my soil based feed or substitute the soil feed for foliar? Sorry for being a pest dude.

 

[mcon]

anyone?

I've never done foliar feeding before would I do that in conjunction with my soil based feed or substitute the soil feed for foliar? Sorry for being a pest dude.

 

[StChristopher]

I'm no pro by any means but, I grow in coco with net pots. Had the same plants (love the BB from GHS). Had a hella time with them yellowing as well. Went from under feeding to over feeding 4 me they were a little tricky. But once you get your PH right and feed right, man do they bush out and the buds seem to just keep swelling. And that plant looks like low N. Its not a heavy hitting high, but it is a smooth great tasting bud. LOL smoking as I type this little Big Bang bud


I would like to add after looking at your plants again, I had an issue with cal/mg with those. You may not but I had to give them a bit more than most other autos I'v grown.

 

[Noods]

mcon, you can give her a sweet Fish Mix foliar any time. Between feedings would be cool. 1 ml/liter is a good dose for a fishy foliar. Do it in the bathtub or shower cuz the fish foliar stinks the place up bad! But it's good stuff.
I didn't see what light schedule you're using, but the best time to do it is shortly after lights go on when the leaves are at their greediest. Spray under the leaves as well and get her good and wet.
Let her sit and absorb the goodies and then carefully shake off the drops. You don't want her too wet, or to have large drops on the leaves that will be magnified by your hps and maybe burn them.
After a day, if you have fish gunk on your leaves, spray her down again with some clean pH'd water, distilled preferably, to clean her up.
:smokebuds:

 

[mcon]

Thanks so much for the responses guys. I'll post back in a few days with results. A.F.N. rules.