All you LED growers, help a brotha out

[k5kolodzi]

i am new to LEDs. I have (2) 1200w Mars IIs. Plants did great during veg and now we are 4 weeks into bloom. Temp is a balmy 74 and RH is between 50-70 depending on time of day. The only thing i have changed in these rooms is the light source. Is there something i missed? Is there something the plants get with HPS and not with LED. I have read stories about people having to add calmag when they switched to LED, but real life experience from someone i can talk to is what im looking for. My nutes are the same. I use Supernatural mildly. About 500-700 ppm as directed. I flush regularly, in fact im flushing today.

Symptoms:
Brown spots/necrosis
Yellowing tips
Leaves are spiraling sideways

* This is not every plant. Maybe 20% of them

 

[Governmentchz]

Re: All you LED growers, help a brotha out.

I may be wrong, but that doesn't look, nor sound like it's your light. I've never heard of anyone having deficiencies due to using LED's, and if it were directly related to the lights then all of your plant(s) would exhibit and not ~20%. CalMag is usually suggested when using RO water, and THAT I can testify to.

I'll look around too, and I hope you resolve this and post your findings.

 

[k5kolodzi]

Re: All you LED growers, help a brotha out.

Figured it out. So I document when I lollipop, defoliate, spray, etc......well my previous flush was documented on the calender, but did not specify if I used a leeching agent or just PHed water. Leads me to believe I had intentions of flushing but may not have. I think I had a salt build up that caused a toxicity/deficiency. Sad. Lesson learned

 

[Governmentchz]

So, have the symptoms been arrested?

 

[k5kolodzi]

Too early to tell. I flushed and then flushed again. Only 2 days in. Nothing seems to be getting worse. I will prune off the heavily effected areas and see if it persists. Thank u all

 

[k5kolodzi]

Here is what i found:

*Jack the Ripper. LED room Approx. 7x12 feet*
Plants are divided up into 2 sides. 20 plants on each side, 1200w LED on each side.
- Pro-mix HP grow medium
- 1 gallon pots
*2 week veg*
- HEAVY flush between nute changes(PHed water only, no cleansing agent)
- Plants are on day 47 of bloom, begin watering schedule now.
- Full lineup of Supernatural Nutrients.
-Supernatural Line up:
Gro Terra 20-20-20
Bloom Terra 15-31-14
Super Boost 11-49-9
Ultimate Thrive 5-0-2
Bud Blaster 1-52-31
Superlicious 3-0-0
Nute schedule by weeks:
1-5 are UT/BT/SL
6-7 UT/SB/BB
8 Flush
Watering schedule= Nute, Nute, heavy water, repeat.
*PHed @ 6.2-6.5*
_______________________________________________________________

I had absolutley no problems in veg. Plants were topped early and growing nicely. Watered with light/medium nutes with no discoloration, leaf curl, nute burn, etc. My problems started about the 4th week of flower. Ladies started to yellow rapidly. I immediately flushed with water and Supernatural's Super leech, followed up by a plain PHed watering about 3 days later. Starting week 5, i started the 2nd phase of bloom nutes. I mixed the nutes to ~600 ppm and proceeded to water. Here is where it got worse. Leaves started to turn yellow at a rapid pace AGAIN.
Here is my theory:
I did what every grower does when they see something new and shiny, oooooooooohhhhh, ahhhhhhhh, I want it!!!!. How hard can it be, right? Well here is what i found.

Using LEDs causes more humidity. A light that produces VERY little heat does not evaporate water at a fast pace. In turn, does not dry out the pots at even half the speed as pots under the equivilent HPS or MH.

Now to the growing medium. I use Pro-mix for a specific reason. Its easy to use, contains very little nutrients(i like to be in full control of that), and retains water very well. However, and this is a very big however, a growing medium that retains a lot of water in a room with lights that do not produce heat equals a pot that is wet for an extended period of time. This can cause many things, including root rot, toxicities, lack of air to the root system, etc. Every room is different, and there are more factors than just the ones i mentioned. Luckily, I believe in lots of air circulation and that helped a bit.

Last but not least, the nutes I used. I like Supernatural. I do not plan on changing anytime soon. If I ever do, It will be becuase I got a screaming deal on the entire line up of something else, and it peaked my curiosity. Supernatural is a one part, salt-based mix as opposed to the very popular 2 part(A&B) that usually comes in a liquid. This allows for easier and faster mixing. Although Supernatural is a salt-based nute, it dissolves very fast and mixes just as well as a liquid. Some people might disagree with me about the faster and easier to mix part, but here is why i believe that. I did some research a while back and this is what i came up with:

*Two and three-part nutrients come in separate “parts” for a reason. If they come into contact with each other when still concentrated (or in too little water) you will see a white precipitate form and, depending on the formulation, this can happen well within a minute or so. you should always add the part containing the phosphate first. This is because the addition sequence of each nutrient ‘part’ can affect nutrient stability, particularly if your water has high alkalinity. “Alkalinity” (bicarbonate & carbonate) is the component of natural waters that causes high pH. Adding the nutrient dose to high alkalinity water can decrease the stability of several nutrient species (including calcium, sulfate, iron, copper, manganese, zinc). Therefore, rather than trying to pre-adjust the pH of the water (often a very difficult task – pH adjustment is better done after all nutrients and additives have been added) it is preferable to first add that part of the nutrient that lowers pH the most. This is usually the part that contains the phosphate. In two-part nutrients this is usually part “B”
-Bob Taylor, chief chemist of Flairform

Of coarse there is alot more to this, so feel free to google it.

So here is where i believe i went wrong. I used a growing medium that retains too much water, with lights that do not produce heat, and a salt-based nutrient. All these products are amazing on there own, but do not make a good combination. With the water sitting in the pot so long, i was having a constant defientcy, toxicity, build-up, etc. i will be trying this room again, this time with bigger plants(personal choice), adding another plain watering into my nute schedule, and using a medium that flushes easier and does not retain as much moisture.

 

[brightlight]

Hello. I am LED grower and would agree that the light isn't the cause. What I see in the top 2 photos is P toxicity and in the last 2 photos is Ca deficiency. The SN products you list show the NPK, but not Ca and other content. Our plant loves her Ca and Mg. I grow organic and include ample amounts of both from different sources.