Def or burn?

[MPL]

Alright I've got two Sensi Star running in E&F under 400w. For the last two weeks, every few days I would find some rust spots or light green tips on older fan leaves on my two plants. Also some dark splotches. I left it alone for about 10 days since the plants have recently recovered from a nute miscalculation (massive burn about 4 weeks ago - miscalculated res size and thus nute dosage was way off - plants have been growing like mad for 2.5 weeks). The growth rate has been phemenonal but I was seeing spots etc. at the rate one leaf every 2 or 3 days. pH was running around 5.5 and EC was 2.0 - 2.2. I figured I had a slight Ca/Mg deficiency so I added 2.5mL per gallon of CalMg+ on a topoff, which brought EC to 2.2 and pH stayed around 5.5. The plants grew faster and the spots seemed less. Yet, they were still coming.

So, here I am about a week later and I decide to add 5mL/gallon of CalMg+ to my res. That was a couple of days ago. The EC was 2.0-2.1 and the pH was around 5.6. This didn't make any difference. I was still getting some slight Mg/Ca deficiency symptoms. Last night I noticed some very slight downward curling of the older fan leaves (only a few leaves) and what appeared to be a bit of heat stress. Well, the canopy is at 80F, but I figured I'd lower the temp anyway and see if this particular pheno of SS is sensitive to heat. I also raised the pH to 6.0 as I felt maybe the lower pH was locking out Mg. Since I thought they might be slightly overfed, I dumped two gallons of the res and replaced with fresh RO/DI water. I lowered the EC to 1.8, pH steady at 6.0. This morning I looked at the plants and they look wayyyyyyyyy worse. In one night I went from one affected leaf (brown spots and light tips on one older fan leaf) to a whole bunch of leaves showing Mg, Ca, K and P deficiencies with little new growth. So, what the hell? Am I starving or burning the plants? I have to go to work and am hoping to have some advice when I get back. I have a feeling they'll look worse yet.

Grow details to follow:

HYDROPONICS/Aero Ponics

How long has this problem been going on? A couple of weeks
What system are you running? (DWC? Ebb flow? Aero? Water Farm? Flood Tables? and so on...) E&F
What STRAIN are you growing? Sensi Star
What was the establishing technique? (Were the seed or clone?) Clone
What is the age of your plants? 4 weeks
How tall are the plants? Would be about 12", but I have them bent over
What PHASE are the plants in? (seedling, vegetative or flower) are the plants in? Veg
What Technique are you using? LST
What substrate/medium are you using?(Hydroton, RockWool etc.) Hydroton
What is the Water temperature? 70F
What color are your roots? White? Brown? Are your roots slimy? White where the nutes don't come in contact
What Nutrient's are you using? How much of each if using multiple? FloraNova Grow, doing addbacks with FloraNova Bloom. Also running 2tsp/gallon of Floralicious Plus, 1mL/gallon SuperThrive, 5mL/gallon CalMag+.
What is the TDS/EC/PPM you are using? Currently 1.8.
What is the pH of the "Tank"? 6.0.
Are you sure your calibration is correct on your equiptment? Yup
When was your last watering? 2 hour watering cycle, 15 minutes on.
What is your water temps? 70F
When was your last feeding change? (ie. grow-bloom-micro-additional) Changed res last night
How often do you clean your system: example: Flush out water replace with clean water and nutrients? I don't.
What size bulb are you using? 400w CMH
What is the distance to the canopy? 12"
What is your RH Factor(Relative Humidity)? Low.
What is the canopy temperature? 78F-80F
What is the Day/Night Temp? (Include flucutaion range) 78F-80F/72F-74F
What is the current Air Flow? (cfm etc.) 250CFM
Is the fan blowing directly at plants? No
Is your water HARD or SOFT? RO/DI
What water are you using? Reverse Osmosis (RO)? Tap? Bottled? Well water? Distilled? Mineral Water? RO/DI
Has plant been recently pruned, cloned off of or pinched Pruned and tied
Have any pest chemicals been used None, no pests.

 

[MPL]

Well, I'm home and they appear a bit for the worse. Little to no growth, a few more rust spots and lots more fringe spotting. Gonna mix a completely new res and start fresh tonight.

 

[MPL]

Ok, fresh res in there. To 10 gallons of water I added: 80mL of FloraNova Bloom, 10mL of SuperThrive and 10mL of Floralicious Plus. I had to use 10mL of pH UP.

EC = 2.0
pH = 6.0

I hope this works.

 

[green giant SA]

good luck bro...check my post in the infirmary...also have a prob with the leaves...yours looking better?

 

[MPL]

Nope. I woke up this morning and there is twice as much evidence of Ca and Mg deficiency. I really don't think I have a toxicity issue right now. The plants have, however, started growing again. I'm at a complete loss.

Can anyone help? The plants are getting worse with a new res, but they have started growing again.

I did foliar spray them about 10 days ago with some epsom salts. This is back when the spotting was very minor. Would this have anything to do with what is going on now?

If I don't stop this soon I don't think the plants are gonna make it.

good luck bro...check my post in the infirmary...also have a prob with the leaves...yours looking better?

 

[MPL]

I installed a titanium ground probe into the res about the time the problems started. I did it to remove stray electricity and help protect me if a pump goes bad and I stick my hand in the res. It's been used in marine aquariums to keep very sensitive corals and fish, so I figured it would be fine for hydroponics. Anyone think this could be a problem? I'm going to pull it out and see what happens.

 

[MPL]

Ok, I topped off my res with RO water.

EC = 1.8
pH = 6.1 - 6.2

I removed the titanium grounding probe. I really don't think this is a problem though.

The purpling that was on the stems was almost gone, but now it is starting to come back.

Plant has restarted growth, though still showing Ca and Mg deficiencies. It also appears worse than yesterday. How long does it take for Ca and Mg issues to reverse, and then how long to start seeing improvement? Or, are affected leaves permanently disfigured?

The EC went down and pH went up last night, and the plants used about 1/2 gallon of water. Total time for the "night" was about 12 hours. That's a good sign at least.

If it is a deficiency, and I let the EC gradually get lower because I think the plant is burning, then the plants will get worse. If it is burning, and I add CalMag or addback FNB to raise the EC and/or Ca and Mg levels, then it will get worse.

I still have no idea if it is a deficiency or toxicity. Blargh. Irritating.

 

[MPL]

I put a lot of thought into the issue and this is my conclusion:

pH of 5.4-5.6 throughout most of the grow slowly led to a Ca and Mg deficiency, as evidenced by the fact every few days a leaf would show up with those symptoms. The RO water made matters worse, as there was no extra Ca or Mg for the plant to use.

When I added 2.5mL/gallon of CalMag+ to the res I saw faster growth, but little reduction in the symptoms.

When I added more CalMag+ the deficiency turned to toxicity, especially since this coincided with an increase of the pH from 5.5 to 6.0. The raise in pH made Ca and Mg much more available, which compounded the extra Ca and Mg I had already added. This last event caused the symptoms to take over a large number of leaves in less than 24 hours. No growth in this 24 hour period.

I changed the res and it allowed the plant to start growing. While more leaves are showing symptoms since I changed the res, I don't think it is spreading quite as fast.

Any thoughts?

 

[MynameStitch]

How big are these plants; sounds like they may still be burned........

It takes time for plants to fully recover from a burn, you always want to start out really light with the nutes and slowly up them after they recover.

Can you get some pictures of the issues?

EC 2.0 sounds very high........

WHat color is your roots? what color is your rockwool? It's not green is it?
The normal brown color?

 

[GANjA_FARmER619]

How are your roots? Are there fungus nats around your plants? Ive had purpling of the stems and massive rust spots which looked like a def. or burn but it was the roots being demolished by the newly hatched nats. It really fucked that grow up. Gnartol works great if this is your problem. Peace

 

[MPL]

The plants, if standing upright, would be about 12" tall. If you counted all the branch length it would probably be a total of about 24"-36" per plant, if not taller.

I noticed it can take awhile for burn recovery. They took almost three weeks to resume normal growth after the initial miscalculation on the res size.

I have been running them at 2.0 EC since they recovered the first time and they've loved it. Very fast growth on all branches. At their peak I think each branch (at least 8 branches) put on an inch every day. A total of 8" of growth in a 24 hour period is fast to me, but for all I know this is slow compared to what experienced growers can pull.

This morning the badly affected leaves look like they are about to die. I don't think there are any new leaves that are showing symptoms. Hard to tell without a functioning camera. Growth appears to have returned to normal - the plant is noticeably bigger and bushier from just looking at it 6 hours ago.

The rockwool is a normal greyish/brown color. The brown comes from the FloraNova. The roots where the water doesn't directly flood are bright, clean white. Where the water comes in contact it is brown. The roots seem very healthy.

I checked for all sorts of bugs last night, both in the medium and on the leaves and I found nothing. No eggs, no flying things, no aliens, nothing. I thought it might have been thrips or something, but so far no evidence of that.

What should I look for when seeing if there are gnats eating the roots? I didn't see anything earlier. As far as I know the only bugs that have been in my house at all are some flies that got in while I was airing out the house (spouse burned some bacon and house was smoky). I'm not too worried about that considering I have a rather fine filter on my cabinets intake. I don't think a fly of any size could get through it.

My res is clean and nearly sterile.

Thanks for the responses!

 

[MPL]

Alright, plants are still growing but leaves are still dying and getting worse. I dumped some of the res and added fresh H20.

I'll let the res stay here for a week or two and see how it goes.

pH needed no adjustment.

EC = 1.6
pH = 5.9

 

[stinkyattic]

Soory- just got your pm but you are in very good hands. Your numbers look good now- one thing I would do is in presence of a known lockout, to supplement your feedings with a fine foliar mist of GH micro to bypass the roots while the plants recover from the burns, and replace needed micros.

BTW, the titianium probe was/is 100% safe for your plants. You can replace it, and it will not react with your fert solution- that's why titanium is so widely used in surgically implanted 'spare parts' in humans. It's as close to being inert as you can get with a metal.

 

[MPL]

Thanks for the advice stinky! You've helped me out on other forums too, and I'm amazed at your generosity.

I have some EJ MicroBlast that I could foliar with. I'll mix it really light and hit them with it this afternoon.

I thought that about the titanium probe and stuck it back into the res. If it wasn't affecting my corals and salt water wasn't corroding it I'm not at all worried about keeping it in my res.

I am also going to get some calibration solution for my EC meter. I just want to make sure it is reading a known solution properly. It's a BlueLab so I'm not real worried about it giving bad readings, but you never know...

Thanks again!

Soory- just got your pm but you are in very good hands. Your numbers look good now- one thing I would do is in presence of a known lockout, to supplement your feedings with a fine foliar mist of GH micro to bypass the roots while the plants recover from the burns, and replace needed micros.

BTW, the titianium probe was/is 100% safe for your plants. You can replace it, and it will not react with your fert solution- that's why titanium is so widely used in surgically implanted 'spare parts' in humans. It's as close to being inert as you can get with a metal.