[deepsoul]

hi folks

my grow has been going really well as you can see from my thread

https://www.icmag.com/ic/showthread.p...0&page=1&pp=15

veging in 2 x 50litre tubs with an aircurtain in each being pumped with a 9litre a minute pump and using canna nutes...

these rusty spots have started to appear very quickly..

any help would be fantastic as this is my first problem...

at the moment I have done nothing except check my ph ec and temps...

ph 5.5 ec 1.6 water starts at ec of 0.3 and temps for water are 19- 24c .. ambient temps between 21 - 27c humididty mainly around 45 - 50.

I have noticed that sometimes when my light comes on after lights out that there is moisture on some of the leaves..

as i noticed that on one plant it had these same rusty spots about a week ago and i figured it had water splashed on it and that had burnt the leaves...

anywayz ..some pics...

[deepsoul]

some leaves have also become very limp on the ends...and some of the larger fan leaves are tairing on the veins.... I cant do much now, but I will get some more air stones and run a second pump tomorow..

I got a spot of this same rust coloring on one leaf of one of my 1 week old plants. It looks just like yours only in just 1 spot. It seems otherwise healthy.

I think it was too close to the light. It was the top leaf on mine that got this and maybe it had moisture on it (not sure now). I dunno, someone experienced might be able to help us.

[mace_ecam]

Mg def maybe, to me it looks like ivc.

how much Mg are you adding? (epsom salt, etc?)

mace

[deepsoul]

umm mace whats ivc?
Im running canna terra nutes in bubblers at nearly full strengh nute.

[Getawaymonkey!]

IVC=intervienal chlorosis
me thinks a mag def mate
1/2-3/4 teaspoon epsom salts dissolved in warm water first, should fix em' right up
Also...do you flush with new nutes to avoid toxins and salts build up? This could be contributing to the deficency
Personally I would empty the res and fill with fresh nutes. This ensures no guessing is necessary

[deepsoul]

yeah mate I empty the tank once a week and start a fresh. I am thinking from doing a bit of reading in the sticky on sick plants that its a ph problem that is causing nute lockout...how this is happening I am not too sure. The worst tank has a ph of 5.8 and the second tank which only has a few spots has a ph of 5.4. I was looking back thru my gro diary and when I started I allways kept the ph at 5.2, but then after a while i would let it rise..I also noticed that after that I mentioned seeing very tiny spots..so it does look like ph spotting...

Now about 4 days ago i forgot to put nutes in the worst tank for about 24 hours but i did adjust the ph down.. I then put nutes back in the tank which lowered the ph below 5 but the plants were not in there for long I dont think...
the worst tank also went for about 18hrs without oxygen as the lid closed the airlines..

I am really disapointed at the few mistakes I have made..but I need to fix them and fix em quickly....

my ec also seems really high for the amount of nutes I have in there..so I think it will be best to flush my tanks out and start again tonight. I am tempted to lower the ph now with ph down but as I keep reading the plants stress from having the ph messed with all the time...

I wonder how long it takes plants to recover from these problems? and any more advice would be excellent

[-Dank Hill-]

Looks like an Mg lockout from a high EC.

Water from the tap is running EC 0.3 or a PPM of 150 or 210 which seems ok.
Your water may be high in calcium.

Depending on which EC factor you multiply by (500 or 700)
you have a total PPM of 800 or 1120 @ 1.6.

No def. symptoms are visible during the first 3-4 weeks.
The 4-6 weeks of growth the first signs of def. appear.
Interveinal yellowing and irregular rust brown spots
appear on older and middle-aged leaves first.

A high EC slows water evaporation and diminishes Magnesium(Mg) availability.
Keep PH above 5.6 and lower high EC for a week.

An excess of Potassium(K), or ammonia nitrogen
and Calcium(Ca) lockout Mg.

On the off chance it is actually a lack of Mg in your nutes.
you can add Epsom salts, how much per gal. escapes me ATM.

Also water temps are high @ 29°C or 84°F, which
reduces dissolved oxygen content and can set
you up for root rot.
You should keep your water temps around 18°C/ 65°F.
59°F or 60°F gives the max. dissolved oxygen content
in water if I remember correctly.

Looks like mag def, next time you water add 1/4 tsp of epsom salt per gallon of water.

[shrike]

Looks like brown spot fungus to me. Try a spray of "Safers" Garden Fungicide, and make sure you spray under the leaves as well.

I assume they are not in flower yet? Which is when to apply the fungicide, if the plants were in flower then I'd just leave it.

Good Luck

Shrike