- White Leafs -

zem

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even though it is normal for plants to have deficiencies in later flowering, i don't think it is normal to have the little leaves coming out from the buds having such symptoms. what to do now depends on how far through you are. if it is a 10 week strain, then I guess that feeding and correcting PH is the best thing that you can do now
 

Hushpuppy

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white leaves usually is a sign of light intensity being too much for the leaves to handle and they become bleached. However, the problem appears to be on leaves that are lower than the buds. If it was light bleaching, you would see it those parts of the plant(buds) that are closest to the light. The other thing that can cause white to appear is iron deficiency. however, iron is less mobile and any deficiency typically shows up in the newest leaf growth, and it would show at the center of the leaf, around the petiole.

I am suspecting that you may have a pH issue or more likely at this point, a toxicity issue. I do notice that you have a little nutrient burn occurring which is not a problem in of itself if it has stopped at being just a little bit of burn. Many off us will push the nutrients to the point of slight nute burn and then back off some so that it stops. However, one thing that can occur later in fflower many times with those who push nutes hard, is a chem buildup in the medium. This buildup of unused nutrients or nutrient salts, will cause a toxic effect within the soil.

If it is as I suspect, a toxic buildup of nutes then I would recommend that you flush the medium with 3x the amount of water as the volume of medium. (If the plant is in 1 gal of soil/medium then use 3 gallons of water. If in 2 gallons of soil then 6 gallons of water) You will need to move the plants in question to a location where the water can drain away, or set them in a large tote on something that elevates them so that you can pour a couple gallons of water into the soil and allow it do drain through, then dup the water that collects. It is very important to do the full amount of water and allow it to drain away from the soil/medium so that it can remove the chemicals that have built up in the soil.

I recommend to anyone who uses chemical(synthetic) nutrients to feed their plants, to flush the soil/medium about halfway through the life cycle of the plants in order to remove the buildup and prevent toxicity. The one caveat to this is organics. If you are growing in organics and feed with organics, you shouldn't need to flush your medium at all.
 

zem

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hushpuppy, I grow in growrocks, do you advise me to do the same too? I don't ever flush except when I first transplant and as long as it is flood and drain and not top feeding, it seems to be okay as the flood will always dissolve whatever salt remains there is from the previous flood...
 

Hushpuppy

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Well with the grow rocks, you don't have as much material for the buildup to attach to, so really ffor you doing a hydro system where you drain and replace the reservoir water, there isn't going to be as much opportunity for buildup to occur. If the grow rocks are real porous, you could conceivably get some buildup in them but I would doubt that its enough to cause you any issues.

The best way to tell if you really need to do a flush is do a system flush like I do, about halfway through the grow(usually about 3rd week of flower) where you just empty the reservoir, refill with just fresh water and then run the system for 6-8 hours then dump that and refill with normal solutions. when you go to dump the flush water, look at it and test the ppm to see just how much buildup is there. If it turns out that you are getting over 500ppm coming out of the flush then it is worthwhile to do it every time. But if you are getting under 500ppm in the flush water then its probably not enough to cause any issues. :)
 
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