Leaf edges curling up

In my experience this issue is often caused by the plants inability to replace moisture to the leaves via the root system as fast as moisture is evaporating from the leaves. This can be from too much wind from fans causing rapid evaporation and drying of the leaves or by temps being too high and it can also be caused by a combination of wind and and heat. Think of it like clothes drying outside on a line. Clothes dried on a bright and warm windy day will dry much faster than clothes dried on a cool overcast day with no wind.
I believe the upward curling of the leaf is the plants attempt to catch and hold moisture from dew and rain and also reduce surface area to slow evaporation. The worse the situation gets the more they curl up.
I have some pics of average and extreme cases where I absolutely know for sure that was the problem because I was able to revive them. More on that later. I'll try to dig the pics up of the leaf curl I'm talking about and post them for comparison.
A couple differences between this type of leaf curl and leaf curl caused by nute burn is that with nute burn old and new growth leaves usually curl down and often have some actual burning. Leaves with nute burn damage are often thick or crispy feeling and dark green from excess nitrogen. Leaves that are wind blown will usually still be soft to the touch and a lighter green than nute burned leaves and often only the newer and more tender leaves are affected.
I have seen cases where it was so bad that the leaf fingers all rolled up into tubes.
Unlike nute burn, you can usually get the leaves to go back to normal if it hasn't gone too far. One way I found that works is to raise the lights high for a few days so you can keep the plants cool without as much need for air circulation and mist the leaves with pH adjusted water periodically through the day cycle and also several times during the night cycle. When you mist the leaves you will see what I meant earlier about the curled leaves holding water. Once the leaves start to uncurl you can start to lower the lights again. Of course you need to correct your wind and/or heat problem first.
I have seen complete recovery from this problem literally over night but it usually takes a couple days.
Remember that you can have cool temps in your grow room and still get curl from even a light breeze.
 

plaguedog

Active Member
In my experience this issue is often caused by the plants inability to replace moisture to the leaves via the root system as fast as moisture is evaporating from the leaves. This can be from too much wind from fans causing rapid evaporation and drying of the leaves or by temps being too high and it can also be caused by a combination of wind and and heat. Think of it like clothes drying outside on a line. Clothes dried on a bright and warm windy day will dry much faster than clothes dried on a cool overcast day with no wind.
I believe the upward curling of the leaf is the plants attempt to catch and hold moisture from dew and rain and also reduce surface area to slow evaporation. The worse the situation gets the more they curl up.
I have some pics of average and extreme cases where I absolutely know for sure that was the problem because I was able to revive them. More on that later. I'll try to dig the pics up of the leaf curl I'm talking about and post them for comparison.
A couple differences between this type of leaf curl and leaf curl caused by nute burn is that with nute burn old and new growth leaves usually curl down and often have some actual burning. Leaves with nute burn damage are often thick or crispy feeling and dark green from excess nitrogen. Leaves that are wind blown will usually still be soft to the touch and a lighter green than nute burned leaves and often only the newer and more tender leaves are affected.
I have seen cases where it was so bad that the leaf fingers all rolled up into tubes.
Unlike nute burn, you can usually get the leaves to go back to normal if it hasn't gone too far. One way I found that works is to raise the lights high for a few days so you can keep the plants cool without as much need for air circulation and mist the leaves with pH adjusted water periodically through the day cycle and also several times during the night cycle. When you mist the leaves you will see what I meant earlier about the curled leaves holding water. Once the leaves start to uncurl you can start to lower the lights again. Of course you need to correct your wind and/or heat problem first.
I have seen complete recovery from this problem literally over night but it usually takes a couple days.
Remember that you can have cool temps in your grow room and still get curl from even a light breeze.
He said there is only one plant doing this in the grow. I chalk it up to genetics most likely. I have a strain that does the same thing through the whole grow but turns out fine in the end.
 

Weedanger

New Member
I had this problem and it was caused by salt accumulation, because my plant was not leaking from the bottom when I was watering. You need to make sure
water leaks under your plants, and take measurements of this water. The PH and PPM should be about the same as what you put in on top.

If you are hydroponics, no idea. Must be cause of temp.
 
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