Trouble with Part of my Aeroponic Crop

Hi everyone. I have a low pressure aeroponic set up. There is no standing water. My cycle is on for 1 min. off for 4 min.

Things have been going quite well. We are in week 3 and the growth appears to be pretty good, but we have just run into a slight problem.

We have two different varieties. Both are growing well, but in the last 48 hours, one has started to show some strange signs of problems with the leaves.

The problem varieties' leaves are more yellow and starting to show brow splotches.

Here are photos of the troubled variety:




Sorry for the quality of the pictures. The light does something weird to the camera. I shot some with the lights out, so that you could compare and maybe tell what's up.

The following pictures are from the other side (part of the same system), which are exhibiting no problems.


Now the only thing i can think of is that we had the lights on for 48 hours and in that time the plants grew within 12 inches of the light face. The only problem is that this is the case with both varieties. Also the lights are vented.

Right now the ph is just under 6.5%. The ppm is 1100 to 1200 ppm of flora grow General Hydroponics nutes.

Temp is nominal 78f to 82 f. We are running co2 enriched atmosphere.

One other thing is that there is slight algae in some of the clear tubes. Not much. Wondering how much peroxide to add, to deal with that.

I'm gonna say magnesium deficiency. Do you give it calmag at all?

Love the space-age looking system btw.

You have Interveinal Chlorosis. This could be a deficiency in magnesium or zinc or a potassium issue or ...
I suspect some sort of nute lockout/toxicity. Maybe those ppm are too high for this strain. The other thing, and this could be a colossal pain ... do you know your pH to be accurate? Much lockout can be traced to pH difficulty.

a cool link to visual deficiency/tox symptoms: http://www.marijuana-seeds.net/Thanks-ThankYou.htm

cheers 'neer

No I didn't. How do i measure magnesium? is it with the EC?

Thanks on the system. This convoluted plumbing allows us to insert the water sprayers from the top, to avoid clogging during growth. It also allows us to remove the water jet locations and check for clogging. Working well so far.

I was wondering. When we did our first water change, 10 days after clone install, we went with the ratio from the chart off the back of the GH bottle. It was one teaspoon per gallon of each of the three nutrients. This came out to 9 tbsp of each for the 27 gallon tank. This amount gave us 1200 ppm. Since then, the ppm is going down about 200 per day. This means that every day i am adding equal parts of each, to get back to that 1200ppm.

Does this seem correct? Are there any other precautions I need to take for this replenishment?

Last, how much peroxide should I add to combat slight algae in a 28 gallon system?

Before my gauge arrived, I was running high 7.1% ph. Since then, I have been hovering at about 6.5. I have tried to lower that with ph down, on a daily basis.

Should I start with magnesium? How do I measure that?

How long have you been replenishing ppms without doing a complete nute change? That could be it right there. Different plants and strains feed at different ratios. If one component is building up because the plants are sucking down the other ions, you will run into lockout/tox issues.
I would do a water flush, perhaps with peroxide, at once, then fill the res with fresh nutrient. Jmo
cheers 'neer

vespa8910 said:

No I didn't. How do i measure magnesium? is it with the EC?

Thanks on the system. This convoluted plumbing allows us to insert the water sprayers from the top, to avoid clogging during growth. It also allows us to remove the water jet locations and check for clogging. Working well so far.

I was wondering. When we did our first water change, 10 days after clone install, we went with the ratio from the chart off the back of the GH bottle. It was one teaspoon per gallon of each of the three nutrients. This came out to 9 tbsp of each for the 27 gallon tank. This amount gave us 1200 ppm. Since then, the ppm is going down about 200 per day. This means that every day i am adding equal parts of each, to get back to that 1200ppm.

Does this seem correct? Are there any other precautions I need to take for this replenishment?

Last, how much peroxide should I add to combat slight algae in a 28 gallon system?

Click to expand...

Hm. I think cannabineer up there might have something if you're giving them such a high concentration. I never go by the recommended dosage straight from the GH chart, and for aero growers, this is especially important. The aeroponic sprayer is a more active delivery system than DWC or Ebb Flow, so it does better on lower ppms compared to those methods of hydro.

Here's what I do. I get a jar of ro water and mix a batch of nute by what the chart says, say I want to mix a strength of 10 gallons worth, I'll put the amounts appropriate for 10 gallons in the mix jar. Once I have this jar of concentrate with all my additives in the right ratios, I simply pour this into my waiting RO res until I have my desired ppms on my tri-meter. I grow by dissolved solid numbers rather than teaspoon mix charts. I have tons left over in my concentrate mix jar (mixed by the chart recommend) that I set aside for manual ppm up injections as the plant drinks. So yes, you're over-feeding... especially for aero.

On a related note, I've come to the firm conclusion through my past three grows that you get better quality weed with milder ppms in Aero. My system isn't straight aero, but it employs low-pressure aero elements along with a robust DWC.

The moral of the story here is that less is more... especially with aeroponics. Ratchet your ppms down gradually... I mean gradually to right around 1000ppm. See how they react to that. If you see positive signs ratchet it down further gradually to 800 or so. When you have your ppms down, it's safe to make up for a little ppm difference with a kiss of Calmag.

Edit:

I've never had algae problems, so that question is for someone else. Any takers? Lol.

cannabineer said:

How long have you been replenishing ppms without doing a complete nute change? That could be it right there. Different plants and strains feed at different ratios. If one component is building up because the plants are sucking down the other ions, you will run into lockout/tox issues.
I would do a water flush, perhaps with peroxide, at once, then fill the res with fresh nutrient. Jmo
cheers 'neer

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Not a bad suggestion. It might be a good idea to give the whole thing a good rinse if there is toxicity due to salt buildup as he suggests. And run lower ppms for god's sake!

lordjin said:

Not a bad suggestion. It might be a good idea to give the whole thing a good rinse if there is toxicity due to salt buildup as he suggests. And run lower ppms for god's sake!

Click to expand...

I fully concur. Running over a thousand ppm is playing with fire ... if you'll forgive the awful pun.

Vespa, I would recommend re-introducing your nutrients at 1/2 the strength you've been using, at least until the gals are back on their "feet". If you must run'em flat-out like you did, imho you're best off changing your nutes frequently. It becomes a game of diminishing returns - marginal improvements in yield-per-grow vs. increased nutrient cost. You'll find your own system's sweet spot in time.
cheers 'neer

<edit> I see my recco differs from lordjin's. Lordjin, is there a danger to dropping it to 1/2 at once?

cannabineer said:

How long have you been replenishing ppms without doing a complete nute change? That could be it right there. Different plants and strains feed at different ratios. If one component is building up because the plants are sucking down the other ions, you will run into lockout/tox issues.
I would do a water flush, perhaps with peroxide, at once, then fill the res with fresh nutrient. Jmo
cheers 'neer

Click to expand...

I have been doing 200 ppm replenished every day for 7 days. We were just getting ready to flush system. We have been maintaining about 1200 ppm.

I am going now to flush system. The how to link above recommends doing epsom salt and folier feeding. I am not sure if the epsom salt solution should be sprayed on the leaves, or if it should be poured into the tank. Should i do a direct nutrient spray to the effected plants?

cannabineer said:

I fully concur. Running over a thousand ppm is playing with fire ... if you'll forgive the awful pun.

Vespa, I would recommend re-introducing your nutrients at 1/2 the strength you've been using, at least until the gals are back on their "feet". If you must run'em flat-out like you did, imho you're best off changing your nutes frequently. It becomes a game of diminishing returns - marginal improvements in yield-per-grow vs. increased nutrient cost. You'll find your own system's sweet spot in time.
cheers 'neer

<edit> I see my recco differs from lordjin's. Lordjin, is there a danger to dropping it to 1/2 at once?

Click to expand...

Hm. Good point about the frequent water/nute changes. That is like hitting the 'reset' button on the dosages of the various elements in the nutes. Re-balancing after the plants have sucked out what they wanted from the old nute solution. I change water weekly even though I have a float switch activated auto refresh system with an external res of plain RO. So I never run into buildup issues.

As for your abrupt change to half strength question, that could shock the plants. They may be just fine if he does that, but there is a chance of shock. Maybe he should downgrade his ppm over the next 48 hrs or so before flushing and re-introducing fresh but weaker nute?

Once you have fresh nutrient, my gut says give it a day. See how the plants respond. If you flush and foliar-feed at the same time, you're doing 2 variables ...
...so I'd hold off on the foliar feed. Evaluate the nute change outcome first. If after two days it's definitely stopped getting worse, but recovery is slow, then a GENTLE foliar feed with N and Mg should help a lot.
cheers 'neer

<edit> Lordjin, saw your post. I don't have experience with plant shock, so I defer. Maybe 800ppm initial?

cannabineer said:

Once you have fresh nutrient, my gut says give it a day. See how the plants respond. If you flush and foliar-feed at the same time, you're doing 2 variables ...
...so I'd hold off on the foliar feed. Evaluate the nute change outcome first. If after two days it's definitely stopped getting worse, but recovery is slow, then a GENTLE foliar feed with N and Mg should help a lot.
cheers 'neer

<edit> Lordjin, saw your post. I don't have experience with plant shock, so I defer. Maybe 800ppm initial?

Click to expand...

OK, I didn't see these posts until I went down and took action.

This is what I did:

1. I dumped the nutrient tank

2. Put a few gallons of clean water in and flushed the system with continuous spray for 10 minutes

3. Dumped that water

4. Put in 20 gallons of fresh water, and per the guide linked on the last page, added epsom salts to the water. The recommended 1 tablespoon per gallon, but I did about half that.

5. I then added the nutrients, which I estimated would result in about 800 ppm.

6. I took some of the epsom salt solution and sprayed the leaves on the most badly effected plants. The concentration was higher than what was recommended in the guide.

NOW tomorrow, I plan to go and dump the tank again and just add the nutrients to 800 ppm. I am doing this becuase I am concerned about this whole epsom salt thing.

I wish I had done a more metered approach, but I was running out of time today and didn't see the additional posts.

I would love to hear some thoughts


Thanks

ps... the folier feed is listed on the other site as being done with the epsom salt solution. I am getting the feeling that this isn't the standard consensus.

cannabineer said:

Once you have fresh nutrient, my gut says give it a day. See how the plants respond. If you flush and foliar-feed at the same time, you're doing 2 variables ...
...so I'd hold off on the foliar feed. Evaluate the nute change outcome first. If after two days it's definitely stopped getting worse, but recovery is slow, then a GENTLE foliar feed with N and Mg should help a lot.
cheers 'neer

<edit> Lordjin, saw your post. I don't have experience with plant shock, so I defer. Maybe 800ppm initial?

Click to expand...

Lol. I don't have experience with plant shock, either. Plants have alien regenerative levels in my system, so much of what I say regarding shock is from what I've seen happen to others... So I know it happens.

vespa8910 said:

OK, I didn't see these posts until I went down and took action.

This is what I did:

1. I dumped the nutrient tank

2. Put a few gallons of clean water in and flushed the system with continuous spray for 10 minutes

3. Dumped that water

4. Put in 20 gallons of fresh water, and per the guide linked on the last page, added epsom salts to the water. The recommended 1 tablespoon per gallon, but I did about half that.

5. I then added the nutrients, which I estimated would result in about 800 ppm.

6. I took some of the epsom salt solution and sprayed the leaves on the most badly effected plants. The concentration was higher than what was recommended in the guide.

NOW tomorrow, I plan to go and dump the tank again and just add the nutrients to 800 ppm. I am doing this becuase I am concerned about this whole epsom salt thing.

I wish I had done a more metered approach, but I was running out of time today and didn't see the additional posts.

I would love to hear some thoughts


Thanks

Click to expand...

You did what you did, right? No turning back now. Just let it ride and keep us posted. I'm sure you'll be fine, but if you see something for the worse, get ready for an emergency flush. Try to have oxygen pumping in your res too. They need all the oxygen boost they can get especially when they're hurting.

Edit:
Oh, how do your roots look, btw? Everything looking okay down there? If you have good healthy roots, I wouldn't worry too much.

cannabineer said:

How long have you been replenishing ppms without doing a complete nute change? That could be it right there. Different plants and strains feed at different ratios. If one component is building up because the plants are sucking down the other ions, you will run into lockout/tox issues.
I would do a water flush, perhaps with peroxide, at once, then fill the res with fresh nutrient. Jmo
cheers 'neer

Click to expand...

I agree,i bet the problems are stemming from you trying to push ppm back up ,also for most strains ive grown the ppm your running is way too high.

If i was you i would lower the ppm to about 800 for the rest of the grow,i would also give it a foliar feed with some nitro heavy nutes.

Ten tablespoons (150 ml, estimate 200 grams) into 76 liters gives me 2500 ppm estimated, just for the epsom salts alone. What ppm readings did you have on this solution?
I also read that you added nutrient to an estimated 800 ppm on top of that. Are you tracking and writing down your actual TDS readings? Will you tell me what they are? I want to be wrong right now.
cheers 'neer

cannabineer said:

Ten tablespoons (150 ml, estimate 200 grams) into 76 liters gives me 2500 ppm estimated, just for the epsom salts alone. What ppm readings did you have on this solution?
I also read that you added nutrient to an estimated 800 ppm on top of that. Are you tracking and writing down your actual TDS readings? Will you tell me what they are? I want to be wrong right now.
cheers 'neer

Click to expand...

I felt weird about the amount of epsom they suggested in the "how to", so I cut it in half.

about 12 tbsp in 27 gallons.

I then added the 800ppm of nutrients.

all together 1500 +_ ppm.

The thing that wasn't clear on the "how to" was wether or not to still add nutrients.

I am going down this morning to dump the reservoir and just use the lower nutrients.

Your posts leave much unclear.

Number one are you ESTIMATING ppm or are you taking readings with a meter.

Two,your post says your using flora grow,is that it ? Your ONLY using flora grow & no other nutrient.

Another question is about your water,what is its ppm & are you taking those ppm into account before mixing up nutes.

One last question,if you are using a multi part nutrient are you mixing each nute seperately or are you dumping all the seperate nutes into a glass,then letting the nutes co-mingle together before adding to the rez.