What is Causing leaf cural?

[denarfer]

Greetings:

I am growing a Barneys Farm LSD strain under one 150w CFL in a DWC system growing in a mix of pebbles and pumas using FloraDuo the ph is at 6.0 water temp 65 under 24 hour lighting with fresh outside air blowing straight on the plant. The humidity has been higher than I am use to running between 63% to73% But within the margin of 60% to 70% for vegetative growth . My concern is the leaves curling at the edges.

I checked both the top and underside of a leaf I cut off with a digital microscope there where no signs of bugs or molds there is no discolorations in the leaves or the leaf edges or along the veins such as burns, drying or spots so it is not a nutrient problem. The temp and humidity of the outside air blowing on plant runs between 68 to 81 night to day with the humidity running between 32% to 58%. I have grown other plants under similar conditions without this happening.
Overall the plant looks healthy exept for what is making the leaves curl at the edges?

 

[Psychild]

Try playing around with the ph some. Try raising it to 6.3-6.4

 

[denarfer]

Greetings: Psychild
If I raise the ph how long will it take to see a change? And have you grown this strain in the past where you would know of other of this plants anomalies?

 

[oceanside]

Do not raise it like he said. This is hydro not soil, completely different ph utilization levels.

Hydro should be 5.7-5.9. Keep it at that ph and let it drop or rise .3-.5 so the plant up takes different nutrients at diff ph levels

 

[oceanside]

 

[Dr. Who]

1: pH in hydro should BE 5.9 - 6.2, I like running at 6.0. Lower is worse then higher......Stay in range, do not play with!

2: That's heat stress.....raise the light up some. Your ambient temps are good. The "felt" temp at canopy level does that to leaves fast. Put your hand at the top of the plant,,feel hot from the light = move it up! BTW, what the leaves are doing is called canoeing. That is a SURE sign of heat stress.

 

[denarfer]

Greetings: Dr. Who and Oceanside

Thank you for your replies you both gave me an idea of where to start looking for more information. I found this web site http://www.growweedeasy.com/marijuana-symptoms and it confirmed that it is heat stress not a ph problem and according to what I have read in multiple publications ph for hydro should be between 5.5 to 6.5 for soil it should be between 6.0 and 7.0.
If it were a ph problem it would show up with leaf discolorations and spots, like your said Oceanside because the plant will not be able to absorb the needed nutrients. For the heat stress the article said to use seaweed extract to help plants recover from the stress Dr. Who have you used seaweed extract before and with what results? And by chance have you grown this strain before? The reason I ask I was wondering if this strain is sensitive to light / radiant heat more than other strains would be? Also will the leaves that are already curled stay that way or will they flatten back out?

 

[weedenhanced]

Greetings:

I am growing a Barneys Farm LSD strain under one 150w CFL in a DWC system growing in a mix of pebbles and pumas using FloraDuo the ph is at 6.0 water temp 65 under 24 hour lighting with fresh outside air blowing straight on the plant. The humidity has been higher than I am use to running between 63% to73% But within the margin of 60% to 70% for vegetative growth . My concern is the leaves curling at the edges.

I checked both the top and underside of a leaf I cut off with a digital microscope there where no signs of bugs or molds there is no discolorations in the leaves or the leaf edges or along the veins such as burns, drying or spots so it is not a nutrient problem. The temp and humidity of the outside air blowing on plant runs between 68 to 81 night to day with the humidity running between 32% to 58%. I have grown other plants under similar conditions without this happening.
Overall the plant looks healthy exept for what is making the leaves curl at the edges?

Nothing to worry only slight curlin its either heat stress of your fan is blowin to hard happened to mine that iam growing now I lifted light dramatically and didnt fix I turned my ped fan down to low and problem stoped

 

[denarfer]

Greetings: weedenhanced
Thank you for the info I figured it was one of two things after Dr. Who pointed me in the right direction either heat from light or the air from the fan being too cold. I already raised the light and nothing happened I have also lowered and repositioned the fan but the leaves are still curling so I am going to get the a seaweed supplement to spray on and put in the reservoir from what I have been reading about it I might just start using it all the time. How long after you turned down your fan before the leaves started to look normal?

 

[Dr. Who]

Greetings: Dr. Who and Oceanside

Thank you for your replies you both gave me an idea of where to start looking for more information. I found this web site http://www.growweedeasy.com/marijuana-symptoms and it confirmed that it is heat stress not a ph problem and according to what I have read in multiple publications ph for hydro should be between 5.5 to 6.5 for soil it should be between 6.0 and 7.0.
If it were a ph problem it would show up with leaf discolorations and spots, like your said Oceanside because the plant will not be able to absorb the needed nutrients. For the heat stress the article said to use seaweed extract to help plants recover from the stress Dr. Who have you used seaweed extract before and with what results? And by chance have you grown this strain before? The reason I ask I was wondering if this strain is sensitive to light / radiant heat more than other strains would be? Also will the leaves that are already curled stay that way or will they flatten back out?

Yes, Kelp extract is a VERY good thing to use.....Many good things are in it. High in trace or "micro" nutrients, B vits, Humic and Fulvic acid. Aids in nutrient uptake (all of them).
Silica is a another thing that could be added to to help out the plants resistance to heat swings.....It also helps prevent bug infestations..It also helps regulate P uptake.

As for your pH zone of 5.5 to 6.5......It would tolerate the low and high for SHORT periods, BUT, your target zone of "best" results would be 5.8 - 6.2.....I try to never let it out of my target zone and adjust daily at lights on, when running my hydros. Sometimes it will hang for a day or two in the range...I get the best results when I do that.....

 

[denarfer]

Greetings: Dr. Who
I know I always try to keep the ph at 6.0 right in the middle of the range. The Silica you metion [ Silica is a another thing that could be added to to help out the plants resistance to heat swings.....It also helps prevent bug infestations..It also helps regulate P uptake.] is it a separate additive or can I get it mixed in with the seaweed? I bought Bio Weed since it was the only brand they carried and plan on including it in my regular weekly feedings. How often should I spray a plan with the seaweed once or twice a week?

 

[vostok]

leaf margins curling is not a ph or food thing in this instance I'd be looking at your inconsistent temps, any way to get your air from someplace else,

see it as the air is hot and the leaf cool...somethings gotta give in this case the leaf margin curls ...upward shedding excess humidity, into very dry air

 

[denarfer]

leaf margins curling is not a ph or food thing in this instance I'd be looking at your inconsistent temps, any way to get your air from someplace else,

see it as the air is hot and the leaf cool...somethings gotta give in this case the leaf margin curls ...upward shedding excess humidity, into very dry air

Greetings: vostok
The air I use is from just outside my grow room and my air temp are always at or around 77 degrees with a high of 81 and a low of 74. So I don’t think it a matter of vast temperature fluctuations and wouldn’t the leaves be the same temp as the ambient air around them?
I think it is more along the lines of what Weedenhanced brought up about air force on the plant from his fan. It not being caused by heat I put my hand over the canopy of my plant and the light position is fine I have changed fan locations and the fresh air no longer blows directly on the plant the fan blowing on the plant now is at 39 cfm. All the condition are as good as they are going to get. I have never grown this strain before so I don’t know if this is a phenotype of this strain. I have done all that I plan on doing for now. The leaf curling has subsided for the most part and it dose not seam to be interfering with its growth.

 

[denarfer]

Nothing to worry only slight curlin its either heat stress of your fan is blowin to hard happened to mine that iam growing now I lifted light dramatically and didnt fix I turned my ped fan down to low and problem stoped

Greetings: weedenhanced
Thank you for the info I figured it was one of two things after Dr. Who pointed me in the right direction either heat from light or the air from the fan being too cold. I already raised the light and nothing happened I have also lowered and repositioned the fan but the leaves are still curling so I am going to get the a seaweed supplement to spray on and put in the reservoir from what I have been reading about it I might just start using it all the time. How long after you turned down your fan before the leaves started to look normal?

 

[rob333]

i have 2 doing that right no u wanna no what i did to fix it ??? lowered my nutes by half a ml somtimes my do it wen they eat to much

 

[denarfer]

i have 2 doing that right no u wanna no what i did to fix it ??? lowered my nutes by half a ml somtimes my do it wen they eat to much

Greetings: rob333
Thank you for the info to bad I feed her today. If the leaf curl continues through this week I will try lower the rate with next weeks feeding. I am running out of thing to modify to remedy this problem.

 

[Dr. Who]

Silica is a separate supplement.
Pro-Tekt from Dyna-Gro
Armor Si from G&H
Are good ones.
Silica's are Alkaline and you should pH your solutions after putting it in and mixing well.

 

[Flagg420]

<-- I use Rhino Skin, cuz imma advanced nutes whore for another yr or so....

 

[denarfer]

Silica is a separate supplement.
Pro-Tekt from Dyna-Gro
Armor Si from G&H
Are good ones.
Silica's are Alkaline and you should pH your solutions after putting it in and mixing well.

Salutations: Dr. Who.
I did a little research and bought some of the G&H Armor-Si. You mix the Armor-Si with the kelp to spray or do I have to put them in separate spray bottle for some reason? I have never used a foliar or for that matter ever sprayed my plants with anything before. From what I been reading it seams like I have been missing a important plant nutritional supplement. I am looking forward to seeing the results. And thank you once more for the information.

 

[Dr. Who]

Nope...silica into res with the nutrition.....

Blah on AN!