I need help BIG TIME!

Im haveing an issue with my plants! there 3 weeks into flowering and i had one die and one is pretty much dead BUT three are doing pretty good but there showing urlier stages of the last two that died! It starts with the leafs curling downward like a claw then purple spots at tips of the leafs! Im only at 250 ppm and there was a yellowy look to the plants urlier in veg stage but i fixed problem with cal/meg! sinse the plants have shown problems i have given them i good flush and i checked run off and ph was 6.18 but i didnt know i was sappost to check ppm so i cant tell you guys that! i also put styrophome and cardboard down on my closet floor cause maybey daytime temps are alittle colder maybey the cold floor is stressing plants?! I need advise! I think it may be a phosfurouse defetioncy but im not sure i need fellow farmers help

as you can see in the pics the picture with full plant is pretty much dead! and the other pics are the plants that are doing good still but i dont want them to turn out like that one so i need to know what im doing wrong

start over i guess???

I'm no expert but looks like nute burn + possible watering issue to me. What's it growing in?

there in soil, im gunna do a water next feeding then nutes if they get better BUT i dont wanna lose these last three!!

Back off with the nutrients dude. You're over doing it.

Looks like you could use a little more light too.

I took them out of grow room for pictures, there under a 400w MH

nfld said:

there in soil, im gunna do a water next feeding then nutes if they get better BUT i dont wanna lose these last three!!

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Are you going to water them, "feed" them, AND give them nutrients? I must be reading this wrong. What is your water scheduling? And what is your nutrient schedule? These aren't necessarly the same, especially since you are growing in soil.

Look through this http://www.icmag.com/ic/showthread.php?t=11688 and when you more have time look through this https://www.rollitup.org/marijuana-plant-problems/38772-guide-diagnosing-plant-problems.html, (THANK YOU!! shenagen for this orginial post and sticky, I've learned a lot!)
I found it very informative, lots of information, lots of pictures to help visualize and actually SEE and compare the symptoms exhibited by your plant.

Good Luck!! Be patient, just use pH adjusted water for now (for soil in the range of 6.0-7.0, although 6.5 is more ideal) and only when needed, overwatering is just as bad.
PS Those damaged leaves will not get green again, look for healthy new growth. There is debate about removing dying leaves. IMO, I've always let the plant make up it's mind when a leaf is no longer useful to the plant.
Good luck again, my fingers are crossed for you!

nfld said:

I took them out of grow room for pictures, there under a 400w MH

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Did all the leaves fall off? Is that why they look so leggy? How close is your light to the plants? I realize it's a MH light and heat & space may be an issue too. Maybe the lack of scale in the picture is making them appear that leggy? But I tend to agree with Snow Crash, they look light hungry.