Brown spots on Lowryder 2, Day 42

Ok I need some help. I have some Lowryder 2's that are well into flowering with some brown spots and a lot of yellowing older and leaves.

1) Any idea what could be causing this? (Pics attached)







Some background:

They grew tall... The one in the pic was at day 42, and she's about 26 inches tall.
Soil is MG organic choice with ~35% Perlite
Veg'd with Mexican Bat Guano (10-2-1) - 1/2 strength
Flowered with Grotek Blossom Blaster (0-39-25) - 1/2 strength
Watered constantly with distilled water pH'd to 6.2
Lights are 12K 250W MH on a 24/0 light cycle
Grow cabinet has a space of 14x27x24

I originally though it was a Mg deficiency so I added one teaspoon of epsom salt to a quart of distilled water, then pH'd to 6.2 and foliar fed the leaves. I ll add some while watering next time because my soil is pretty wet now.

I added the bat guano as a tea and developed slight nute burn during vegging, so when I started to flower I chose something without nitrogen as I thought there was enough in there. I have a decent amount of yellowing leaves, and I know some is normal during flowering but on one plant, practically every fan leave is turning yellow.

2) How can I combat mass yellowing of fan leaves during the flowering stage? Should I let it go, will it eventually affect my buds? Foliar feeding a nitrogen supplement?

Additionally, one of my LR2's stems are slight purple to reddish.

3) Could this be related to my other problems? What can I do to remedy this? It is only on one plant, who otherwise is pretty healthy; med green leaves, one yellow leaf, average LR2 height.

Im 2 and a half weeks from harvest, and I dont want my crops to be spoiled. Any insight or help would be greatly appreciated. Thanks for your time.

That my friend is a complete lack of nitrogen, feed them some veg food and you will be fine

Problem is that your food doesn't have any N in it, and contrary to what you might have heard..... MARIJUANA GOBBLES A SHIT LOAD OF NITROGEN DURING FLOWERING.. I'm willing to bet that it started to yellow around then 2-4 week of flowering??

max316420 said:

Problem is that your food doesn't have any N in it, and contrary to what you might have heard..... MARIJUANA GOBBLES A SHIT LOAD OF NITROGEN DURING FLOWERING.. I'm willing to bet that it started to yellow around then 2-4 week of flowering??

Click to expand...

Thanks. Will I be OK adding 1/4 strength tea (1 tsp/ gal) from the Mexican bat guano, or should I use something else? Is 1/4 strength not enough to get them back on track. should I add a stronger mix. Id rather not go out and spend more money on more nutes.

Yep, started around the 2nd week.

So would I be fine just using a tea from the bat guano I have (10-2-1)? I ask, because I was told this was best for the vegging cycle. Im 2 and a half weeks to finish, and I dont want to affect the bud formations by adding the wrong supplement. Thanks in advance.

J