First grow got some curling

[Bigrick31]

In this grow room there are 2 different strains. There are 4 Grand daddy clones and 2 sour diesel clones. The clones are in styrofoam cups until they get a little bigger which is when they will be put into 3 gallon pots. They are being grown in Fox farms potting soil which states not to use any nutrients for the first 30 days as the soil already contains enough nutrients for the plants. The clones are under a 400w metal halide for vegging then they will be switched to a 600wHPS for flowering.
When the clones were first put into the room the light was set about 9" away from the plants, An exhaust fan was running 24/7 and so was an oscillating fan. The room started to get up to 85 deg F at which time some leaf curling was noticed. The light was raised up to 17" away from the plants and the oscillating fan was removed in exchange for a 9500btu portable AC which now keeps the room at 72 deg F and the humidity at 45. However leaves are still curling. A combo moisture/ph meter is used for testing the plants. Testing the PH of the plants sows they are at about 7.75PH. As for watering the plants are tested twice a day and water is added when the meter first starts getting into the red zone The meter reads moisture on a scale of 1-10 water is added when the meter reads at 3 to avoid over watering. Can anyone tell what may have caused the leaf curling and if anything should be changed to prevent further damage to the plants?

 

[CiderSpy]

Did you not poke holes in the pots for air and drainage ?

 

[Bigrick31]

there are 4 holes in the bottom of each styrofoam cup

 

[doc111]

In this grow room there are 2 different strains. There are 4 Grand daddy clones and 2 sour diesel clones. The clones are in styrofoam cups until they get a little bigger which is when they will be put into 3 gallon pots. They are being grown in Fox farms potting soil which states not to use any nutrients for the first 30 days as the soil already contains enough nutrients for the plants. The clones are under a 400w metal halide for vegging then they will be switched to a 600wHPS for flowering.
When the clones were first put into the room the light was set about 9" away from the plants, An exhaust fan was running 24/7 and so was an oscillating fan. The room started to get up to 85 deg F at which time some leaf curling was noticed. The light was raised up to 17" away from the plants and the oscillating fan was removed in exchange for a 9500btu portable AC which now keeps the room at 72 deg F and the humidity at 45. However leaves are still curling. A combo moisture/ph meter is used for testing the plants. Testing the PH of the plants sows they are at about 7.75PH. As for watering the plants are tested twice a day and water is added when the meter first starts getting into the red zone The meter reads moisture on a scale of 1-10 water is added when the meter reads at 3 to avoid over watering. Can anyone tell what may have caused the leaf curling and if anything should be changed to prevent further damage to the plants?

7.75 is way too high of a pH. It needs to be more like 6.3-6.8. I would also think about transplanting ASAP. I bet they are rootbound or getting real close.

 

[Bigrick31]

7.75 is way too high of a pH. It needs to be more like 6.3-6.8. I would also think about transplanting ASAP. I bet they are rootbound or getting real close.

Ill transplant now then. The ph of my water is at 6 but after I water the plants the soil reads 7.75 what do you recommend to remedy this?

 

[doc111]

Ill transplant now then. The ph of my water is at 6 but after I water the plants the soil reads 7.75 what do you recommend to remedy this?

FF soils are supposed to be pH adjusted to 6.3-6.8. Testing runoff isn't a real accurate way to tell your soil's pH. I would transplant and see what happens. Try to keep your water in the 6.3-6.8 range. If you are using FF soil for the transplant maybe test with a soil pH kit or soil tester first. It should be good though.

 

[Bigrick31]

Ok just finished transplanting. Tested the soil before the transplant any you are correct the fox farms soil read 6.7ph. I did note some spotting on a couple of the plants dont know if it helps narrow down the problem. I also noticed when I went into the room the heat from the AC isnt being sucked out of the room instead its coming out of my light. Anyone know how I can get 1 exhaust fan to remove heat from the light and heat from the AC without either coming back through the hoses. what I did was tap into the duct that goes to the roof for the bathroom exhaust fan. A "T" was cut in and a new hose goes to another exhaust fan duct is then run from that exhaust fan into the grow room where another "T" is installed. one side of the "T" goes to my light and the other to the AC I figured the exhaust fan would keep the heat from traveling back through the light but i guess now. The room is staying cold but the AC is working harder than it should.

 

[xxplosive42o]

Heat Stress = Curling Tips + Brown Spots and/or Brown Tips

Nitrogen Toxicity (too much)= Curling Tips

Copper Deficiency= Curling Tips + Yellow-White Lower Leaves (develops later)

Hope that helps! I just browsed through like 300 pages of my book to find those!

Let me know if you ever solve the issue! Take it easy!

 

[Bigrick31]

Heat Stress = Curling Tips + Brown Spots and/or Brown Tips

Nitrogen Toxicity (too much)= Curling Tips

Copper Deficiency= Curling Tips + Yellow-White Lower Leaves (develops later)

Hope that helps! I just browsed through like 300 pages of my book to find those!

Let me know if you ever solve the issue! Take it easy!

Based on those descriptions sounds like heat stress thanks! hopefully they make a speedy recovery.

 

[Splifford]

Hi Bigrick31,

Your plants are suffering from Nitrogen toxicity, your soil is running way too hot.

Whenever you see your leaves curl under and they start to dry out and crisp, they are suffering from too many Nutes.

You will need to flush your soil with 3 parts water to 1 part soil. After the flush give them about 2 weeks and they should recover.

Your PH level of 7.75 is way too high, but what has happened is due to the high PH level, it has opened up the channel to Nitrogen feeding which is what is now burning your plants.

 

[doc111]

Hi Bigrick31,

Your plants are suffering from Nitrogen toxicity, your soil is running way too hot.

Whenever you see your leaves curl under and they start to dry out and crisp, they are suffering from too many Nutes.

You will need to flush your soil with 3 parts water to 1 part soil. After the flush give them about 2 weeks and they should recover.

Your PH level of 7.75 is way too high, but what has happened is due to the high PH level, it has opened up the channel to Nitrogen feeding which is what is now burning your plants.

I disagree. The plants don't have the characteristic dark green appearance coupled with "the claw".

 

[Bigrick31]

Hi Bigrick31,

Your plants are suffering from Nitrogen toxicity, your soil is running way too hot.

Whenever you see your leaves curl under and they start to dry out and crisp, they are suffering from too many Nutes.

You will need to flush your soil with 3 parts water to 1 part soil. After the flush give them about 2 weeks and they should recover.

Your PH level of 7.75 is way too high, but what has happened is due to the high PH level, it has opened up the channel to Nitrogen feeding which is what is now burning your plants.

Im wondering how the PH got so High seeing as the Soil has a PH of 6.7 and my water has a PH of 6. I just transplanted from the cups to the 3 gallon pots you still think a flush is necessary or should I wait and see how they react to the transplant and also see if the PH levels out? Im not adding any extra nutrients to the soil I dont see how they could be receiving too many nutes.

 

[illegalalien]

i don't like Styrofoam or white plastic cups they let light in to your medium, and green slime can't be good .
i like small seedling tubs with seed raising mix.
i water with an atomizer of weak seaweed concentrate as a root stimulant.

when the third set of leaves has emerged they are ready for transplanting .
you want to see a dedicated root ball with healthy white roots.
you may have left them to long in those cups.
also if you are using the type of ph/moisture meter i think you are, well frankly there crap .
i had one of those 2 pronged things , i think it was called a green genie, the ph meter was hopeless and the moisture meter not much better.
practice makes perfect.

 

[doc111]

Im wondering how the PH got so High seeing as the Soil has a PH of 6.7 and my water has a PH of 6. I just transplanted from the cups to the 3 gallon pots you still think a flush is necessary or should I wait and see how they react to the transplant and also see if the PH levels out? Im not adding any extra nutrients to the soil I dont see how they could be receiving too many nutes.

I doubt your soils pH was actually 7.75. Testing runoff isn't an accurate way to tell soil pH. If you start out with a good pH just make sure you keep your water and nutes pH'd and you'll be good. Don't flush just yet. Wait for a few days and see how they do. I don't think you had nitrogen toxicity. You would see some other telltale signs. Best of luck my friend.

 

[Bigrick31]

transplanted them They seem to be doing just fine. No new curling. Will the effected leaves come back or will the stay curled? Should I leave them on the plants or cut them off?

 

[Bigrick31]

Now that the curling has stopped I have a new problem. Some of the leaves are turning yellow. The room is at 69 deg F right now and 50% humidity. So i doubt its heat stress. Any thoughts on the yellowing? I have not added any extra nutrients to the plants water as of yet because the FF soil says its not needed. Im aware that one of the most common causes of yellowing is lack of Nitrogen. I have some Flora Nova nutrients should I add that to the water next time I water the plants?

 

[Bigrick31]

My 2 sour diesels needed some water so I mixed a little bit of Flora Nova and Floralicious into the water i gave them ive been reading all the problem/solution stickies and all I could come up with was they are deficient in something/s hopefully it works.