Heat stress?

[BillyBud420]

Hey all,

My grow room got warmer than normal last night and I think my plant is showing heat stress.

The plant was leaning over to one side so I propped it up with stakes. Does it look like heat stress?

I move the lamp (150w HPS) up a bit to 8" above the plant. Checked surface temps at leaves and they are 74f.

Any thoughts? What sort of recovery can I hope for?

Thanks!

 

[Major PITA]

You moved the lamp UP to 8" away?
If so, then I'm surprised she isn't more burned. When my plants had to deal with heat, they curled more taco-like, so I can't be sure. I'd assume it is heat related as well. She should recover.

 

[Emilya Green]

I dont see any heat burning... I see very wet soil and a plant trying desperately to evaporate water, and clawing a bit because she is getting too much of a nute load and maybe a burned leaf tip from those nutes too. What is that soil? Have you added nutes? How often do you water? Are you using the lift method?

 

[BillyBud420]

Thanks to you both for the reply.

I have two fans blowing across the plants and the temps at the tops have always been in the mid 70s (even at 6" away). They are now reading somewhat lower than that.

I started feeding yesterday (after 10 days) with the botanicare schedule listed on this forum in the FAQ. I have always taken your advice Emylia on watering and the pots were essentially dry before watering and feeding last night. (Both via lifting and use of a moist/wet probe)

I'm also using PromixHP and RO water. All water and Feedings are at 6.0.

In a different post, you (Emylia) suggested that the Promix has very little organic nutrients and that Feedings each watering may be a good idea.

I'm assuming that the reduced feeding schedule listed here is too much for my plant at this stage and imagine I should scale it back. (I fed at slightly less than half of what the manufacturer suggested for my first feeding..)

Thanks so much to both of youfor your help! This is my first go round at this and am really trying not to screw it up too badly!

 

[Emilya Green]

Thanks to you both for the reply.

I have two fans blowing across the plants and the temps at the tops have always been in the mid 70s (even at 6" away). They are now reading somewhat lower than that.

I started feeding yesterday (after 10 days) with the botanicare schedule listed on this forum in the FAQ. I have always taken your advice Emylia on watering and the pots were essentially dry before watering and feeding last night. (Both via lifting and use of a moist/wet probe)

I'm also using PromixHP and RO water. All water and Feedings are at 6.0.

In a different post, you (Emylia) suggested that the Promix has very little organic nutrients and that Feedings each watering may be a good idea.

I'm assuming that the reduced feeding schedule listed here is too much for my plant at this stage and imagine I should scale it back. (I fed at slightly less than half of what the manufacturer suggested for my first feeding..)

Thanks so much to both of youfor your help! This is my first go round at this and am really trying not to screw it up too badly!

Thanks for the clarification Billy. I answer a lot of plant problem questions on several forums throughout a typical day, and sometimes I do get confused. This too is why it is best to start up one thread on your current grow, which allows us all to go back and see what has transpired before the immediate question.

Now that I am caught up, you are correct on the feeding of nutes at this point, per my earlier recommendations, and although that is what I remember saying to you, I failed to mention that for new seedlings, generally 1/2 or even 1/4 nutes is usually called for. Good call on only going with 1/2 strength! Your plant is definitely clawing a bit in reaction to too strong nutes and that explains the burnt tip. No biggie... you will adjust and the next watering will be just right and the burning of leaf tips will stop and the clawing will go away. Some would get frantic at this point and call for a flush of the excess nutes... but its not that big of a deal really... she has been through worse.

Also, congrats on successfully using the lift and probe method on your last watering, and I am sure that you are well on your way to a fully recovered plant since this is the case. At least now all you are getting is what looks like the beginning stages of overwatering, that crinkled leaf effect, instead of a full blown nitrogen deficiency caused by shut down roots, and resulting in yellowing or dying leaves at the bottom.

You are indeed recovering, and even though you are now doing things correctly, it is still going to take about 3 wet/dry cycles to repair the damage and get on with things. So again, all of my points in the last post were correct ... I see no burning from heat, but I do see a bit of over fertilizing, and still the indications of damaged lower roots... but not as bad as last time! Just keep doing what you are doing, and you will see a dramatic turnaround in a couple more waterings. Do a google on canoeing of leaves if you would like to see what being too close to the light, but still not getting burned looks like. Canoeing that goes upwards is from heat. Canoeing that goes downwards is from over watering. I mention canoeing because yours are NOTdoing it, so I knew that your plants were not overheated. Your descriptions of the temperature both this time and last, do not indicate that heat is the problem in your grow area either... just a bit of watering too often as we discussed before. You know what to do now, so just relax, keep doing what you are doing, smoke a bowl, and watch the show. ---Em

 

[BillyBud420]

Thanks for the clarification Billy. I answer a lot of plant problem questions on several forums throughout a typical day, and sometimes I do get confused. This too is why it is best to start up one thread on your current grow, which allows us all to go back and see what has transpired before the immediate question.

Now that I am caught up, you are correct on the feeding of nutes at this point, per my earlier recommendations, and although that is what I remember saying to you, I failed to mention that for new seedlings, generally 1/2 or even 1/4 nutes is usually called for. Good call on only going with 1/2 strength! Your plant is definitely clawing a bit in reaction to too strong nutes and that explains the burnt tip. No biggie... you will adjust and the next watering will be just right and the burning of leaf tips will stop and the clawing will go away. Some would get frantic at this point and call for a flush of the excess nutes... but its not that big of a deal really... she has been through worse.

Also, congrats on successfully using the lift and probe method on your last watering, and I am sure that you are well on your way to a fully recovered plant since this is the case. At least now all you are getting is what looks like the beginning stages of overwatering, that crinkled leaf effect, instead of a full blown nitrogen deficiency caused by shut down roots, and resulting in yellowing or dying leaves at the bottom.

You are indeed recovering, and even though you are now doing things correctly, it is still going to take about 3 wet/dry cycles to repair the damage and get on with things. So again, all of my points in the last post were correct ... I see no burning from heat, but I do see a bit of over fertilizing, and still the indications of damaged lower roots... but not as bad as last time! Just keep doing what you are doing, and you will see a dramatic turnaround in a couple more waterings. Do a google on canoeing of leaves if you would like to see what being too close to the light, but still not getting burned looks like. Canoeing that goes upwards is from heat. Canoeing that goes downwards is from over watering. I mention canoeing because yours are NOTdoing it, so I knew that your plants were not overheated. Your descriptions of the temperature both this time and last, do not indicate that heat is the problem in your grow area either... just a bit of watering too often as we discussed before. You know what to do now, so just relax, keep doing what you are doing, smoke a bowl, and watch the show. ---Em

Thanks so much! I will wait until the pot is fully dry and reduce my nuts to 1/4 when I water next.

I am so thankful for all of the veterans who take the time to help out is rookies!

 

[Emilya Green]

Thanks so much! I will wait until the pot is fully dry and reduce my nuts to 1/4 when I water next.

I am so thankful for all of the veterans who take the time to help out is rookies!

I am glad to be able to help. We were rookies once too. Karma is very important to someone growing in a less than legal place, and I feel it very important to pay forward what was once given to me, to protect that Karma. I was one of the hard-headed-thought-I-knew-it-all ones too (some would say that hasn't changed); so it was a good thing that some old ones took pity on me to show me where I was wrong. I learn new things every day too, and that is one of the other reasons that I try to write down my thoughts and log my experiments. If you really want to master a subject, try organizing your thoughts enough to be able to teach it. I learned that as a Jr. Professor teaching economics a few years ago as I worked on my dissertation, and I now apply those same lessons, practices and disciplines to this avocation.

 

[BillyBud420]

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I am glad to be able to help. We were rookies once too. Karma is very important to someone growing in a less than legal place, and I feel it very important to pay forward what was once given to me, to protect that Karma. I was one of the hard-headed-thought-I-knew-it-all ones too (some would say that hasn't changed); so it was a good thing that some old ones took pity on me to show me where I was wrong. I learn new things every day too, and that is one of the other reasons that I try to write down my thoughts and log my experiments. If you really want to master a subject, try organizing your thoughts enough to be able to teach it. I learned that as a Jr. Professor teaching economics a few years ago as I worked on my dissertation, and I now apply those same lessons, practices and disciplines to this avocation.

You 'voice' is very effective and you have a clear knack for instruction!

One more quick question. I was thinking about skipping the nuts entirely at the next watering and begin feeding at 1/4 strength the two waterings from now. Would this be advisable? Or should I return to feeding when I water next? (Remember, I'm basically running a hydro grow since I'm using Promix which has very few organic nutrients)
Thanks again for all of your help!

 

[Emilya Green]

The reason that hydro grows tend to grow a little faster and a little bigger than typical soil grows is that you have the advantage in hydro of being able to give nutrients every time. If you do this in soil, the nutes and salts build up and your plants can get in trouble, but in hydro, this doesn't happen and you are able to give more nutes more often, and make them grow faster as a result.

So, I personally would recommend nutes almost every time adjusted to the ppms appropriate for the age of your plants. About once every 3rd watering or so, run ph'ed water through there once as a flush of any accumulated salts and carbon, and to clear out unused nutes and I think you will be golden, but I will also advise you that this is my personal opinion and that there are many other opinions out there as to what the best way to use promix is. Some will give nutes every time, no exceptions... others say to go every other time or even every third time. Make up your mind how you want to do it, be consistent, take notes and see how it goes. There really are no rules here.

Emmie

 

[BillyBud420]

The reason that hydro grows tend to grow a little faster and a little bigger than typical soil grows is that you have the advantage in hydro of being able to give nutrients every time. If you do this in soil, the nutes and salts build up and your plants can get in trouble, but in hydro, this doesn't happen and you are able to give more nutes more often, and make them grow faster as a result.

So, I personally would recommend nutes almost every time adjusted to the ppms appropriate for the age of your plants. About once every 3rd watering or so, run ph'ed water through there once as a flush of any accumulated salts and carbon, and to clear out unused nutes and I think you will be golden, but I will also advise you that this is my personal opinion and that there are many other opinions out there as to what the best way to use promix is. Some will give nutes every time, no exceptions... others say to go every other time or even every third time. Make up your mind how you want to do it, be consistent, take notes and see how it goes. There really are no rules here.

Emmie

Hi again,

It seems I may still have an issue with the leaf edges curling which I am sure is just the residual nuts from my previous feeding but thought I'd post an update.

Here was the new growth one day ago. (Note that the new leaves are not curled...the old ones still are)

Top day, however, I can see evidence of the new growth starting to curl at the edges...

It has been 5 days now since I have fed/watered and my pots still have some weight.
The temp in the room is 77 and the temp at the canopy was 80.

I have 2 fans in the tent that are pointed up at the light... They are not directly hitting the plants but there is plant movement due to the air currents they are creating.
I've moved e light up somewhat and the leaf temp is now 76. Rh - 50% I also angled the fans so that there is less evidence of air current...although the there is still plant movement.

Any thoughts? I don't think my temps are that extreme...and am thinking my previous feeding is still affecting the new growth.

My plan going forward is once the pot is totally light, to give a watering with straight PH 6.0 RO water u til I get significant runoff....then let the pots dry again. Then go with a 1/4 strength feeding.

 

[Emilya Green]

how far away is your light? This sure looks like heat stress to me.

 

[BillyBud420]

how far away is your light? This sure looks like heat stress to me.

My light (150 watt HPS) was 9" above the plant. Temps at the leaves were 80f. (Verified by IR laser thermometer) Temps in the room were 77f.

As mentioned, I moved the light up to 10" and the leaf temp is now 76.

 

[Emilya Green]

despite the temp, 10" appears to be to close... try a foot.

 

[BillyBud420]

despite the temp, 10" appears to be to close... try a foot.

Thanks! I will give that a try.