1 plant yellowing, but the other is just fine (1st timer)

[THIS BUD 4 U]

I have 2 gals sitting side by side and both get watering together and on the 12/12 light cycle. They are in to the 5th week of flowering, but one looks great the other one it looks like all of the leafs are turning a light yellow and from head to toe.
Anyone with any ideas? This is my 1st attempt at this and up to now things have been looking good. I should have trimmed a few more leafs when in veg. stage, but I'm learning.

 

[2clean]

some strains turn yellow and needs more nitrogen,prob too late to add alot but u can add just alittle.. best thing to do next time is monitor the color of the leaves first 3 weeks of flowerings and add nitrogen when u noticed it turns light green.. when u add,u wil noticed a difference in color the next 3 days..

thats a secret manyh people dont know thats y their leaves turn yellow by the 5thw eek and plant stunts and they end up not yielding as much as they want.. I did a side by side experiment and i can tell u this.. also pay attention to all these people posing pictures..
you noticed the guys posting pics with there leaves still green past the 5th week,their stuff comes out spectacular..

now look at all the people with plants yellowing by the 5th week.. look at their end results and judge..
theres a difference between good and great. y have good when u can have the best

 

[BuddroGreen]

Pictures would help..pH? Soil or soiless?

....naturally in fifth week of flower you might see a few lower fan leaves yellowing, just a few...if it's a lot, might have an issue.

You should not be using a lot of (N) Nitrogen in flower, you should be lowering your (N) Nitrogen before the fifth week of flower for a 8 week strain, if it's a Sativa and 12-16 week might be using a little (N) Nitrogen in week 5 flower, (P) Phosphorus & (K) Potassium is what you want to increase in flower....slowly.

 

[Dan Ultra]

Pics are really needed.

If you need you need help uploading there are some links and video tutorials in my signature to help.

 

[2clean]

I have 2 gals sitting side by side and both get watering together and on the 12/12 light cycle. They are in to the 5th week of flowering, but one looks great the other one it looks like all of the leafs are turning a light yellow and from head to toe.
Anyone with any ideas? This is my 1st attempt at this and up to now things have been looking good. I should have trimmed a few more leafs when in veg. stage, but I'm learning.

I forgot to tell u that u should buy overdrive. It will green up the leaves alittle and make your buds bigger. It's a bloom booster. Also add some carbs. It will add alittle green.

 

[shadykeli]

Whats going on here it is only on 2 plants ??

 

[Dan Ultra]

Looks like the start of cal/mag deficiency. What type of water are you using and whats the ppm?

 

[shadykeli]

I am using tap water. First time grower. ppm I don't measure anything expect for nutrients per gallon and for that I just follow instructions on bottles.

 

[Dan Ultra]

Do you know what your pH is of the water you are giving? As well as your soil?

 

[BuddroGreen]

Looks like a pH issue.

 

[shadykeli]

I don't know the ph I have been told that tap water is good and that the soil is made for growing canibis and here was no need to test. Guess I was miss informed. Why would it only be 2 out of the 7?

 

[BuddroGreen]

Soil pH should be 6.5. You can use tap water, mix your nutrients into water, and then pH nutrient solution to 6.5.

I'm not a soil grower, but in hydro if the pH at the root zone gets all wacky, some of the same signs are seen, not knowing the pH of the root zone in your soil can cause all kinds of issues, especially nutrient lock out. In hydro we keep our nutrient solution at 5.7 -5.8 works best, cannabis likes it a little more acidic in hydro.

 

[Dan Ultra]

pH is important because certain nutrients can only be absorbed within a certain pH range. See chart below. If your soil is out of range, you are missing important nutrients that then sit in the soil and cause lock out.