Problem Yellow Leaves

right come on lads i need help...i got 3 big bud x white widow plants on the go...at 4 weeks in the bottom leaves all of them have gone yellow...i gave them some nutes that i used in the past which worked ok and still the leaves are yellow...my ph tester says the water is 7-7.2....is this bad enough to cause the yellow leaves..did some experiments with vinigar in water and managed to make a change in the water...do i need to do this all the time in the future.....or is this problem something else...the plants are in a stealth box with a 45w cfl 3-4 inches above which worked on my last grow fine....my ph tester was from a garden center probe type thing cost 8quid so not a brill one gonna buy a litmus paper tester that changes colour tmoz to test the water properly...oh lights are on 18 hours..got a computer fan blowing air in and a passive exit which again worked last time temp in their is 75....plants look healthy up untill start of week 4.....5 weeks 3 days now.....need some advice on what to do or what it might be....cheers lads.

yeah brother id either add more water and adjust ph or add more nutes then adjust ph. The prob is you dont have a pic so i cant see if its nute burn which is most likely the cause and will need to be addressed by adding more water or dumping the water and starting over to lower the concentration of salts.

pH wise you need to be 5.5-6.0 5.8 being heaven

Another reason i cant tell you whether your burning em or not is cuz some of your nutes would be locked out (might as well not be there) which could perpetuate a nute deficiency. Hope this has been enough enjoy those 'maters.

Sounds like a lack of light. With low wattage growing, the plant reaches a certain point where the light is only able to penetrate a certain distance down, so as the plant grows, it sheds off those lower leaves that it can't support, since there's a lack of photosynthesis.

A 45 watt cfl is hardly enough light to get you through, that's basically adaquate lighting for seedlings only.

My guess is a nitrogen deficiency but you should put some pics up so we can see.
usually nitrogen deficiency starts from the bottom leaves and moves upward.
what type of nutrients have you been using and what type of soil???

and your ph shouldn't go over 6.5

Dystopian said:

yeah brother id either add more water and adjust ph or add more nutes then adjust ph. The prob is you dont have a pic so i cant see if its nute burn which is most likely the cause and will need to be addressed by adding more water or dumping the water and starting over to lower the concentration of salts.

pH wise you need to be 5.5-6.0 5.8 being heaven...............

Another reason i cant tell you whether your burning em or not is cuz some of your nutes would be locked out (might as well not be there) which could perpetuate a nute deficiency. Hope this has been enough enjoy those 'maters.

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If your in soil, then this is the WRONG advice.. You soils ph should be between 6.3-6.8 (adjust water to the same), with the ph being so low your gona run into lockouts. NUTE BURN DOESN'T CAUSE YELLOWING, usually it's lack of light or lack of nitrogen

max316420 said:

If your in soil, then this is the WRONG advice.. You soils ph should be between 6.3-6.8 (adjust water to the same), with the ph being so low your gona run into lockouts. NUTE BURN DOESN'T CAUSE YELLOWING, usually it's lack of light or lack of nitrogen

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With out Photo's it is hard to tell what the trouble is. But from your discription, I would say that MAX is correct. In every way. PH of 5.8 is way to low for soil, which i am guessing you are using, and Yellowing leafs down low are probable to low of Nitrogen, or a Lockout like MAX said. And those PH drops and Litomis paper are not very accurate at all. they are like +/-1 full PH. Spec Scientific has a very nice quality PH pen with Temp for only $38 USD. This pen is better then most of the $80-$120 pens I have had.

cheers lads took a reading from my water with the tester i got and it was 7.4 sometimes reading more...so i experimented with some citric acid and made up a load of 6.8 water then flushed them...took a reading in the soil and 6.8 was the result..however the top new leaves are starting to go now..i will try and get some pics on here by tonight for you guys....cheers lads much appreciated

.....this is my veg set up...they only in here while veg...dont think light is the problem....anyway what do you lads think the prob is...cheers

Looks like a PH trouble which is causeing a Nitrogen lockout. The yellowing is the lack of Nitrogen, the dark brown dots I have had when my PH is out of wack. Fixing the PH is not like a magic wand. It will take a little while for the plant to correct itself. The yellow leafs might turn a bit greener, but do not expect them to turn a nice health green.

To fix your ph, get some dolomite lime and sprinkle it on the top of your soil and then water as usual.. The lime will take a bit to start working but it will eventually buffer your ph to a good level

thanks lads i attacked the ph levels with some citric acid to bring the levels down to 6.8..ive also made up a few bottles of corrected water for future use..i presume i have to do that from now on because my tap water is reading 7.5ph....roughly how long does the plant take to start looking healthy again or as good as its going to get anyway...cheers lads.

if you can get some ph down, i think I read somewhere that citric acid can fuck with your ph

Water with a PH down additive. Shouldnt need to go extremely low, the soil (once corrected) will maintain it for you. Watering with ph above 7.0 ALWAYS causes lockout of nitrogen on my ladies. Atm, some are fighting the same thing. I repotted and went ghetto by rinsing in the tub and floating em in our ph 7.6 water. I was hoping the ladies wouldnt notice the change up, since i bathed in 5.8 nutes immediately after. Alas, nitro lockout and yellowing. Dont fret however, they ALL recoverd fine, took about 3-5 days as usual. When I say recover, I mean, the newest younger leaves came in green and healthy. Unfortunately, the more mature leaves retained a slight yellowing. A side note, I noticed some hairs (probably stress induced), hopefully no hermies. Two lessons learned.

1: Dont flush in 7.6 ph tap water when repotting
2: Dont repot from a crappy tub that takes a fight to get ladies out of!

Hope this helped some. I do run an ebb and flow setup, but in soil it all remains the same theory. Dont buy into the 'lower ph by 2 pts and hr or less crap'. I dont know how the hell someone could get that to workout in soil. Just start ph'ing your water when you add it. Ive been using Advanced Nutes ph down. Its SOOOO strong and has a fine shelf life. Im sure its brand named priced, but it goes sooo far, the price is negligible. Also, more lights would help, but if youve used that setup before, maybe it isnt that. Currently my white widow is the shortest plant Ive seen so far. That, and not really the fastest grower.
Happy growing to ya!!

max316420 said:

is your ww from gh?

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Mine is, with all the work, why not go for the best. GH is hands down my first choice of fems, EVERYTIME!! Sadly, they are losing money as my cloning is now 90%. Ill say it again, WITH CONVICTION!! GreenHouse seeds the bees knees!

nice mine are gh too, i just cut some clones off her today, rooted one about a week ago and now its veggin but im really excited about them. That plant roots quick, i think it rooted in like 6 days

dont know if you can see but the top leaves are dry and curled under..rest of the plant is nice and healthy just them top leaves...any ideas lads...cheers...this is my greenhouse grow by the way.

Any way you could get some better pics?

strangelistener said:

dont know if you can see but the top leaves are dry and curled under..rest of the plant is nice and healthy just them top leaves...any ideas lads...cheers...this is my greenhouse grow by the way.
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Either those are crappy photo's, or those are not weed plants. Even the one close and on the right looks to have smooth edges on the leafs. What kind of plants are they?

its the out of focus plant at the front...the plants in the background are tomatos and other veggies...my camera is shit so sorry about that but you can just make out what is going on...the top leaves are dry dull and curling under making the top surface dome like the other leaves are not bad but the new groth at the top look like they are going to be bad....again ive been watering with 7.4 ph water unknowingly.....which i have sorted now...put some lemon juice over the soil and sprayed the top soil to get the juice soaking down without watering as i flushed them with corrected water 2 days ago and dont want to overwater them and cause more stress on them...any ideas....cheers lads.see the post below this

hope this is a bit more clearer for you..cheers..oh they are baby toms in the back..its actually white widow..