Is this heat stress?

[morphRx]

On some of my plants I'm running into this 'burnt leaf' problem. It's a brown, rust color that forms starting on the edges of the leaves, and slowly forms on almost all of the leaf...

Past 2 days I haulted all foliar sprays and will go back to them when plants seem better.


I just want to check with you guys to make sure why this is happening. So please post your opinions or educated guesses..

Thanks

 

[Shortied1986]

My plant is doing that as well

 

[trichomes]

that spray can cause this if you spray when its hot, on the leaf surface. straight water can even do it in bright sun, good luck, take a look at the "leaf chart" it"s in one of my recent thread replies I posted.

 

[Shortied1986]

I was also told this could be a pest problem to

 

[trichomes]

yes, I saw the spots, have you seen any critters? they always leave trace evidence, gotta figure out which problem you are fighting...???

 

[Shortied1986]

I have previously seen a couple real small orange bugs but I wash my leaves and used an organic pesticide but the orange spots still appear only not as fast now. On top of that I have recently used a fogger in my grow room with my plant covered with a sheet

 

[morphRx]

No pest problems here. I have used sprays in the sun which may have caused the magnified burn spots... Like I said, I've haulted all foliar sprays and gonna see how this plays out...

 

[trichomes]

the bugs probably made the spots, leaf edges look burned, that is a unrelated to the spots, thats my guess

 

[Shortied1986]

Makes sense

 

[Fuzzy Duck]

Mmm difficult to tell at present...


I might look at total quanity of nutrients used... as to cause nutrient burn or def ?

On the other hand its appears like a P-phosphorus def with a touch of Ca- calcium def...



It may help if you provide more information to help solve the problem...

As in growing medium used... i suspect either soil/compost or coco coir ?

Nutrients used if any ? & what brand of nutrients ?

Stage of growth may help also, as some nutrient defs are common depending on stage of growth !

 

[morphRx]

UPDATE:
Alright so I'm gonna give a full run down in specific detail as much as I can. Here's some new pics of the whole plants with the leaf burn issue... I just talked to the guy at the hydro store, he told me to bring in my run off water so he can test it and look at it, says if I'm putting in like 800ppm and getting out 1200ppm then theres a lock out or salt build up happening... Anyways, here's the info..


Soil: FF Ocean Forest

Nutes: Just switched from FF Trio to Advanced Nutes MGB, B-52 w/ Pro-Tekt, Cal-Mag Plus. Only 1 nute feeding with the AN since the switch, and I just watered today with distilled water & pro-tekt w/ cal-mag.

nute dosages per 1 gallon
MGB - 12 ml (first feed at full strength each)
B-52 - 8 ml
Pro-Tekt - 1/2 tsp
cal-mag 1/2 tsp

When I watered today the PH was about 6.0-6.5, but my run off was like under 4.0 (using a vial and solution dropper testing, no digital.)

I just recently got a digital PPM reader so I'll be more on top of it... I didn't get the chance to test the PPM of the run off water since it just came to mind and plants were watered hours earlier...


Is this heat stress or a nute burn?... What can I do to help fix the issue?

 

[Fuzzy Duck]

800 PPM to 1200 PPM measuring run off is a pretty poor method to be honest...


The reason it may well be so high in run off in PPM is that the run off is picking up trace mineral/chemical salts as it pass's through the soil ! effecting end measurement of run off which will always be totally different to what you started out with either with PH/PPM/EC.

 

[Fuzzy Duck]

Had i a bit more time to think about this whilst at work today

Heat stress will cause the outer edges of the leaf to curl upwards which is normally assoicated with HPS/MH lights being to close for comfort of the plant, some times reflector design can create a focused heat spot which may burn the leafs normally a set point with in the tent which gets effected.


As i'm not total aware of your past feeding regime with FF trio ?

It may of caused a mineral/chemical salt build up in the soil leading to nutrient burn symptoms & possible nutrient lock outs due to adverse PH conditions if regular feed with nutrients over a period of time !
(most nutrients are mildly acidic with a salt build up effecting PH of growing medium)

A jolly good flush should be applyed for good measures normally 3 X the quantity of water of the pot size should be passed through the growing medium... e.g 1 gallon pot use 3 gallons of water to flush.

After flush apply a 50% strength nutrient feed.


When feeding with mineral/chemical salt nutrients a feeding regime off - feed, water, feed etc can be used to help prevent build up of harmful salts in in growing medium, kind of helps let the plant use up available nutrients in between feeding so toxicity issues are less likely to occur.

 

[morphRx]

UPDATE:
PROBLEM DIAGNOSED

Big issue. Nutrient burn. There was a heavy salt build up in my soil, I did a 1 gal flush this morning and the run off was 2200+ PPM!! I had flused with 10ppm distilled water! I just finished doing a 2 gallon flush, run off was around 300+ppm and ph of 6.0, very good considering circumstances!

Another plant I just did a 2 gal flush too. First gal of flush was 3000+ ppm! ran another gallon through and brought it down to 500+ ppm with a ph of around 5.5..

Both plants had a gnarly build up in the soil and it was bringing the pH down to like 3 or 4, it was crazy...


I'm going to give them 50% nutrient strength next feed if they are looking better, but I might hold off on the nutrients for a week or 2. I was going to flower this weekend but since this problem occured I'm going to let them recover for another week or 2...

 

[Jimmycricket]

I was about to say it looks like a pretty obvious nute burn and potash deficiency.

 

[morphRx]

I took care of the 2 plants that were the worst.. I have another that's doing super good right now but I'll be checking the run off of that one tomorrow or sometime soon. I'm hoping this flush fixes the problem and they recover within the next week so I can put them into flower soon... I'm just a bit concerned with the lack of nutes now since the flush, and I also had watered them yesterday and did the flush today so the 2 have been overwatered but should bounce back from their wilting within the next few days. I'll keep an eye on them to see if I notice any defencies and feed at a quarter strength if need to..

 

[Fuzzy Duck]

Looks like you got things under control


But what leaf damage has occured will not repair & at least the flushing will prevent further nutrient burn type symptoms...

You might get mild defeciencys show in the next few days after such a large flushing some people may apply a 1/4 or 1/2 feed after the flush to help ward of any defs whilst waiting over watering of flush to dry out a little before commencing with a more suitable feeding, watering regime.

 

[morphRx]

It's already been 2 days since the flush of the first 2, I don't think I want to water them again with 1/4-1/2 strength nutes as they are already over watered as is. I'll keep a close watch though and if they show they need nutes then I'll supply them with it. I'm still watching new growth for any leaf burn to see if problem is under control for good.

Thanks for the advice, I had considered using small bit of nutes after the flush but I just wanted to make double sure it was the build up and over fertilization that was the problem.