please help + rep Leaf tips getting dark green almost black or dark brown

well the Leaf tips are getting dark green almost black or dark brown and these are the big fan leaves and the tips of the new growth at the top is turning brown. wtf

first off i water with sink water

its in miricle grow dirt

and i fert them a small amount once a week

It could possibly just be the strain, could you post some pics?It would help alot.

well the first three pixx are from today i put the whit paper so it pops a lil bit more and the fourth pic is from 2 days ago when i put them to flower and this happend over night

Really it could be a few different things so its kinda hard to tell just from pics. What nutes. are you feeding them and how often? Whats the ph of your water and how often are you watering them and how much? Mine are kinda doing the same thing with new growth dips dieing and I finally narrowed it down to being a (P) Phosphorus def., even though im giving them alot of phosphorus right now there not getting it because ive never flushed my soil and ive got nute. lock out from it and thats why my plants arent getting the phosphorus they need

i dont know the ph in my water.... i guess i should know i also have 3 other plants and they all get the same water and fert why would it happent to one and not the others? should i just flush them with some nutral water and just see what happens?

it looks like its gonna rain today i think ill just put it out side to flush it

any ideas what it may be should i start giving it bloom ferts???? if so what is good?? i just flushed all my plants whith filterd water

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i found this online this is the way the tips of my older fan leaves look but the tips of the new growth are brown and crispy

its supposed to be a p deffi just want to make sure

as for bloom nutrients, everyone is going to have a preference.
Since you just flushed maybe letting them dry up a bit would be a good idea.

Most of us see a problem and then try 3 or 4 things to correct the problem, this Normally adds more problems to the mix.

Most everyone will say when you decide to introduce nutrients, begin with 25% strength and look for response, some plants may want more, or less (Nutes and/or water) than those of the same strain.

Are you "resting" your water 24 hrs+? removes chlorine.
Are you using "warm water" ? If you rest the water at a temp closer to the soil temp you can try to avoid shock from colder water.

I am sure you are going to get a plethora of information. Good Luck and Happy Gardening!

ok well thank you ive been doing so much shit wrong its not even funny i have not been letting the water sit i figured my water was ok cus i gave tap water to my last grows.... and i flushed the plants but i think the water was prolly like 75 degrees and my grow box is like 80-85 yeah and i think that makes sence i should just let it sit for like a day and see if it gets worse.........

another pic

+rep any one?????????????/

hellllooooooooooooooo

it's a P deficiency. new young growth is turning brown as well?

nope the new growth has the very tips turning light brown.............you think is might be a p def and heat stress it was only one plant out of 4 tho

and how would i fix a p def???

Looks to me like you are overwatering.

Im no expert, but my buddies looked the same and it turned out to be over-fertilized. Worst comes to worst, if there are multiple plants, you should try different remedies for different plants and hope 1 shows a quick sign of recovery.
I have always used tap and "rested" it. No problems for me.

i water once every 3 days or when they start to droop...........and i fert like once a week and its only like a .3 of fert for all 4 plants