Can't identify spots??

[Aussiebloke]

Trying to determine the cause for these spots and patches drying up and dying on lowest leaves... rest of the plant is fine and healthy.

 

[ShimmyBob]

This is actually exactly what my plants looked like before the problem got worse. (See link below) You'll need to provide some additional info on your setup, humidity, nutrients, temperature and maybe some more pictures etc. before people here will be able to help you. I really hope that we can figure out what's causing it between the two threads.
Would be good to see the underside of the leaves since could always be pests. If you're actually from Australia there could be venomous flesh-eating spider mites the size of my hand hiding under there

 

[Aussiebloke]

Haha yeah I'm from Australia alright, using LED viparspectra 600w temp avg 21°c to 29°c and avg between 30% and 60% humidity... using advanced nutrients sensi grow A & B and using calmax in coco cior using 1/2 recommend nutes for the time being. Ive been ranging my PH water from 5.5 to 6.5 and when i PH test the over flow water after a feed it comes out at P.H 6.2... im going to PH down to 5.5ish and flush them for 2 waterings then introduce nutes back @ half strength...
should i be adding calmax every single water regardless of nutes? As i only nute up the water every 2nd or 3rd feed.

I will supply some more photos shortly.

Cheers

 

[Mr.furley]

I give all my nutes & add in's every other, and just PLAN PH'ED WATER the other.

 

[Aussiebloke]

No Title

Underside of the leaves.

 

[alltatup]

If you only feed plants once in three weeks, that could certainly be a deficiency. It sure can't be nute lockout.

Why not try feeding LESS on a weekly basis? I feed weekly, but far below what AN recommends (which I use, too).

 

[Aussiebloke]

I usually water them every 3 days every second water has nutes and cal mag the other is just straight PH'd tap water... i do beleive ive been going overboard with watering them as i fill the pot and pick it up and tip it to drain the excess myself... going to try a PH flush in a few days when it dries out abit more and only add a moderate to small amount of water... and go from there. Thank you for the help guys!

 

[Aussiebloke]

No Title

It has moved upto the next set of leaves... plant seems to have slowed right down on new growth... it is 4 1/2 weeks old and from seed... its got me stumped?? Any help??

 

[Mr.furley]

Hey bloke,
So first off you are going to need a bigger pot, your plant is at 4.5 weeks and leaf span is larger then the pot.
1) transplant soon.
2) Like alltatup said they need a little more nutrients.
here is a example from my grow.
Monday night or Tuesday morning I flush my 5gal pots with 1.5gal of Ph'ed water on Friday night or Saturday morning I give 3/4 to full strength nutrients and calmag in about 1gal of water, then I repeat depending on how dry my coco is for the appropriate above-mentioned days.
If you are at 1/2 nute three days later water and then maybe three more days more water then three more day 1/2 nutes your coco is depleted and your plant is starving.
it's sound like everythings in check from your description except for this. this is only a suggestion and I hope this makes sense, more importantly hope this helps.

 

[D.A.A.S.69]

Have you tried a different way to double check your PH?? Could be ph meter is not working right.