yellowing and brown spots???

This is my second grow, my two white rhinos are in the 2nd week of flowering. Recently I noticed that the large fan leaves towards the bottom started turning slightly yellow, and started developing these small brownish spots on the veins. Today I checked my girls and the problem is getting worse! There is now a handful of leaves that are yellowing with these nasty looking, brown, necrotic spots... I am not sure what could be the problem. I am feeding per the fox farm feeding schedule, every other watering, using tap water that has been sitting out for at least one day. Is it a calcium deficiency??? Please take a look at the pics and if you know what could be the cause please PLEASE help before my girls die on me. Thank you in advance.

That to me looks normal, as in.. the canopy above blocks light to the lower leaves, making them die.

here check this out----hope it helps if so hit the 'cred-button'

Quick Deficiency Guide
Nitrogen: Entire plant is light green in color; lower leaves
are yellow; growth is stunted....
Phosphorous: Entire plant is bluish-green, often developing
a red or purpleish cast; lower leaves may be yellow, drying
to a greenish-brown to black color; growth may be stunted...
Potassium: Leaves have a papery appearance; dead areas along
the edges of leaves; growth is stunted...
Magnesium: Lower leaves turn yellow along the tips and
margin and between the veins; the lower leaves wilt...
Calcium: Young stems and new leaves die...
Zinc: Leaf tissue between the veins is lighter in color;
yellowed; papery in appearance...
Iron: Leaf tissue appears yellow, while the veins remain
green...
Copper: Leaf edges appear dark green or blue; leaf edges
curl upward; young leaves permanently wilt...
Sulfur: Young leaves turn pale green, while the older leaves
remain green; plant is stunted and spindly...
Mananese: Growth is stunted; lower leaves have a checkered
pattern of yellow and green...
Molybdenum: Leaves are stunted, pale green, and malformed...
Boron: Young leaves are scorched at tips and margins...

Could be a phosphorus deficiency. Are they flowering right now?

Subscribed....I got the same problem, but mine is only a couple of leaves towards the middle and the top

Thanks to all for your suggestions... after doing some more reading I am pretty certain that this is leaf septoria, a fungus that consumes the leaves and sometimes even the stalk.

During my first grow I kept the same conditions as now, but with way less nutrients, this leads me to believe that my current problem is not due to deficiencies, since my plants thrived with less nutrients during my first grow. The only thing I changed was I added a humidifier in my room, since Colorado climate is very dry and I was registering a relative humidity of under 20%. With the humidifier running, I increased the humidity to anywhere between 50 and 70%. I then looked in "Marijuana Garden Saver" and found a picture almost exactly like what is happening to my plants under 'leaf septoria', a fungus. It was then simple to connect the dots... Since fungi thrive in moist environments and the only thing I changed was I increased the humidity... and the book described the symptoms as a fungus... Bingo!

So now for prevention (J.C. Stitch, "Marijuana Garden Saver"):

1) If you have affected leaves, cut them off and dispose. The affected leaves contain spores of the fungus and should be eliminated to stop it from spreading.
2) neem oil
3) copper fungicides, including Bordeaux mixture, can slow the disease
4) sulfur

Control:

- Bacillus Pumilis (beneficial bacteria)
- cinnamon and clove oils
- compost and compost tea
- copper
- coriander oil
- neem oil
- pH Up
- potassium bicarbonate
- sesame and fish oils
- sodium bicarbonate
- trichoderma (beneficial fungi)

My solution: I cut off all the affected leaves, and retired the humidifier. I will purchase some neem oil, as I am learning that neem oil is a miracure for a variety of diseases and pests.

Hope this helps!

BeefSupreme said:

Could be a phosphorus deficiency. Are they flowering right now?

Click to expand...

Yes Beef, they are in flower and showing very nice flowers. That is another possibility because phosphorous deficiency shows similar spotting, except that the spots are not confined to the veins of the leaves, like they are with leaf septoria. That is the one key distinction it appears.

Although some might recommend different, I've always kept my humidity at 40-50% in veg, no higher. Im bloom, I try to keep it between 20-30%, sometimes it drifts a little lower. 70% is a little high, but you should still run your humidifier if it gets down below 30%. You might want to buy a thermostat that controls humidity(can't remember what they're called.lol), and then the humidity will stay constant.

I have the same problem (septoria). However, I can't seem to stop it. I've used Bacillus Pumilis (which smells like ass), and neem oil. I have also drenched the entire room with bleach. Yet each day I look more leaves are infected. One plant is looking dire. It has almost no sun leaves left, and still each day more of its leaves are infected. I am about 2 weeks into flowering. Is there any hope? What concentration did you use for your neem oil? I am removing leaves at the first speck of infection is that the right thing to do? Any help would be appreciated.
P.S. for the record I am not certain it is not a Ca difficency.

that is tragic---I watched a video Seemore Buds and they showed a room infected and how they rectified the situation. Bleach at 20% solution sterilizes the equipt also do not mix outside tools with inside. The plants are like us surgery needs to be sterile/ cloning. I wash my pots with soap and water before I plant. Neem Oil (dunk bath upside down) is great if your not flowering---but in your case ?? I do know that Ammonium Sulfate which you should have around anyways if you keep your soil at 6.75 - 6.5 it comes in a bag 21-0-0 anyways a mixture of that like a tbsp to 16oz sprayer bottle will help erradicate most bugs and things too. FYI if you mist them with water when you water that is when I do it. If your Wet soil PH is at 7.1 max to 6.3 lowest--- all nutes are available, If it was new soil the nutes are there just not accessible to her. Good luck on that and Sterilize everything after this crop.

I think I have a case of this leaf septoria. It started on a AK-47 I have growing I removed all the effected leaves just to see it spread to the healthy ones. Now it has somehow moved to another plant. This pic is of the newly effected Red Dragon. I was thinking of trying the neem oil but idk at what concentrate. Any suggestions?

1first pic looks like a classic pH problem...what is ur pH before you water them?
and if not that then maybe Mg or P or K deficency..either way a good flush/feed(pHd to 6.5ish if ur in soil) should help

Ganja Geek said:

I think I have a case of this leaf septoria. It started on a AK-47 I have growing I removed all the effected leaves just to see it spread to the healthy ones. Now it has somehow moved to another plant. This pic is of the newly effected Red Dragon. I was thinking of trying the neem oil but idk at what concentrate. Any suggestions?

Click to expand...

Yes this def looks like septoria.... all you can really do is cut off the affected leaves. It seems that once the plant is infected it will spread indefinitely and there is not much you can do to contain it. Best bet is to start over and make sure all your ingredients and equipment are clean, fresh, and sterile. This is very sad, my condolences bro.

You guys think this looks similar i thought it was a mg problem but it started at the veins...