Great White Shark - Nute Burn or Heat Burn?!

[RoninStrain]

Hey Gang-

I had started growing an indica strain (Great White Shark) about two weeks ago under about five CPF's in Roots Organic soil and everything was going extremely well. The plant was healthy as could be and the only issue I had during this stage was a little excessive nitrogen (extremely lush green color) so I stopped fertilizing, which didn't seem to bother the plant in the least.

I made the upgrade to a 600 watt hortilux hps bulb just two or three days ago and some pretty dramatic problems started to reveal themselves very quickly. Photos should be below. The only difference from before was the different light bulb obviously & a transplant to a much larger container in Roots Organic soil. I also continued to hold of on any fertilization. I tested the Ph with a digital meter and it seems to be at the proper level as well.

So my questions are these:

Is this simply heat burn? Do I just need to ventilate more/move the lamps.

If not, is it a nutrient deficiency? Any way to tell which nutrient?

Is it an excess of some nutrient? Remember I'm not fertilizing at this point so any nutrient burn would have to have come from the Roots Organic soil, and I'm not sure if soil right out of the bag would contain those level of nutrients or not.

Or perhaps its another problem altogether that I havent considered!!!?!

Any help or advice would be a blessing. Thanks much!

 

[ShutUpDonny]

Ronin -

First I want to say that I'm IN NO WAY A PRO, so my questions aren't meant as directives. But that won't keep me from answering! And in the meantime hopefully other more experienced folks will chime in.

Anyway, I suspect that the damage you're seeing is due to heat stress, if not straight up burning. CFLs are great lights for veg (I'm using em now), but they are much less powerful and generate much less heat than HIDs. This you can probably tell just by sticking your head into your grow area.

Basically, when you make the switch from CFL to HID you will want to make sure the plants are mature enough to handle the intensified light, you will want to hang the HID _MUCH_ further from your plants than the CFLs were, and you will want to keep an eye on your temps and humidity. So:

How far is your light from your plants?
How big is your grow area?
What is the temperature and RH% (relative humidity) inside it?
Are you running any ventilation?

Get back to you in a bit...
>D

 

[ShutUpDonny]

Also - what medium are you growing in? You may want to close this thread and repost it in a more specific area...

 

[RoninStrain]

Hey Donny-

Appreciate the response. I've answered your questions below.


How far is your light from your plants?
Well, on day one they were only about 18 inches, but I gradually have raised them since I suspected they were burning the plant, and now they are nearly 40 inches above the plant tops.

How big is your grow area?
The plant itself is inside an old wine barrel and the lights are hanging from the ceiling. The barrel is a standard sized barrel of about 50-60 gallons so its relatively average for a "closet-type" grow space.

The first day I just set the reflector right on the rim of the barrel. Later I took the temp inside of it and it was insanely hot (100+ degrees). Thats when I first noticed the damage.

Since then I have raised the lights considerably to about 40 inches, drilled two dozen 1'' holes at the base of the barrel for ventilation and added a small fan inside of the barrel to help circulate air. Since I've made these changes the temp has been perfect at 70-75 degrees.

What is the temperature and RH% (relative humidity) inside it?
The temp is now steady at about 70-75 degrees and the relative humidity is 43% currently.

Are you running any ventilation?
Yes, a small fan at the bottom of the barrel.

Would the initial high temp inflict this kind of damage to the plant do you think?
Should all that dead stuff be trimmed off or would that be irrelevant?

Thanks!!

 

[RoninStrain]

And the soil medium is Roots Organic's 'natural and organic potting soil'.

 

[ShutUpDonny]

Yessir - 100 degrees is way too hot. You'll want your plants to not really go much over eighty, or I think 90 if you pump in CO2. For vegging you will also want to keep the humidity right around 65-70%, though lower it when you get to flowering.
With the high heat you had, the plant was under a lot of stress, and with the low humidity it was probably having trouble photosynthesizing, so both of those things led to the damage you see. But moving the lights up like you did, adding a humidifier, and generating a lot more airflow will all really help. And if the leaves haven't gotten much worse from what your pictures show then I bet they're still usable. You'll need them in order to grow new healthy ones.
What are you doing for nutrients, and how often are you watering? Oh yeah, and hang on to this link for the future.
How to Grow Marijuana Everything You Need to Know
The first thing listed under "Nutrient Deficiencies & Sick Plant Symptoms" is a great resource, but there's great info throughout that whole page.

Good luck man!

 

[Mr. Krip]

Ronin, what's your PH???

(BTW...it does look like heat stress, with the leaves curled up, but also possible K deficiency)

 

[Mr. Krip]

Actually, here's two links to help you diagnose plant problems:

Cannabis Plant and Pest Problem Solver: Pictorial

Nutrient Disorder Problem Solver

 

[Twinkie]

Oh that brings back bad memories. That happened to me i would bet my last dollar that is very high heat stress. The good thing is it will not be long before you know if it will survive. I would venture to say it will come back with a little tlc. Mine was as bad and it survived so just wait all will probably be ok.

 

[RoninStrain]

Thanks for the advice ya'll.

Mr K. - I tested the soil Ph and that was fine.

It does seem to be back on track although growth is extremely slow.

Any ideas on how to jump start growth following heat stress?

 

[Mr. Krip]

Try a little SuperThrive mixed in with your next feeding. It helps minimize stress and brings back the vigor.

 

[RoninStrain]

REJOICE! We're back on track. I had to let it veg for quite a while after it recovered to get a decent amount of real estate for the buds to grow on but it's come roaring back. Below should be a picture 5 weeks into flowering, with three/four weeks to go. Note the wine bottle next to the pot to get some idea of its scale.

If you've never considered it, think about trying Great White Shark. It's a very fun grow and the smell is sooooo great.

Thanks for your help!

 

[mudrunner]

wow... that really came back from the heat stress nicely, gorgeous plant man! kind of amazing when you think about it, how much these plants can go through and still have the determination to grow through all kinds of stuff.