yellowing,and black edges

Hello all, I hope someone here can help. These plants are about 4 or 5 weeks into flowering. At first they only started to turn yellow then the edges started to turn black. Any ideas what might be wrong with them? Any help is better than no help!!!

maybe a phosphorous def

Hey, i was think maybe a p or more a k def which has led to some form of infection, simply as if it was ph or over/underfert,it would be brown edges which are dry,Quick q, are the edges dry and brittle or soft and still attached?
Maybe also your night temps could be dippin to far and thats why the edges have gone black instead of brown, i had leaves turn purple from a temp of below 10 degrees c night time temps....


Sorry not much help,, maybe help from the bump

they are kinda dry and brittle when the blackness first starts it is not brittle after a day is when it starts to dry up a bit. the plants at first for a week or two where very light green and into a light yellow now the edge thing and dying leaves now

Feed them.........feed them a well balanced meal. They are starving to death, the lightening of the leaves were your first indication. If you don't do anything else get some 10-10-10, good luck and welcome to RIU.

canefan said:

Feed them.........feed them a well balanced meal. They are starving to death, the lightening of the leaves were your first indication. If you don't do anything else get some 10-10-10, good luck and welcome to RIU.

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Do what he said ^^

You need to up your nutrients in general like canefan said but i would say that the visible problems are mostly potassium related.

Mr. Anomaly said:

You need to up your nutrients in general like canefan said but i would say that the visible problems are mostly potassium related.

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Yeah he has a few problems, lol, sorry not funny to the grower but that is why I went with the balanced NPK. New grower don't want to overload him.

I gave them some 10/15/10 and the black edges got worse but the past couple days they are looking sweet again. I believe with the 10/15/10 they got nuts burn so I flushed them. its been 2 days now and they are looking good. in the next watering I will give them half the recommended dose of ferts. Thanks for the Help!!!