Yellowing/Spotting

[tokeroo]

I would be most appreciative if someone can help diagnose this issue. I am a new grower and have tried to diagnose this myself, but so far I have not had much luck. Some of the lower leaves are yellowing, and a few are showing spotting. The spots are brownish in color and seem to start mid-leaf.

The yellowing is proving to be a too hard for me to pin down. I originally thought it was a nitrogen def, because it was affecting lower, older leaves first while the upper newer leaves were very green. Now I am noticing some of the lower leaves are getting yellowing veins instead of the main leafy party (the margins?), while others are yellowing in the margins/leafy part.

The plants pictured here are two plants in one 2.5 gallon pot. Probably not the smartest thing to do, for sure, but I was doing a little experimenting at the time, and I have limited space atm.

They are two different types of bagseed, so genetics are crap, which may itself be the issue.

I am growing in Miracle Grow with the stupid time-release stuff. Please don't bash my soil choice, unless you are sure the soil itself is causing my issues.

I am using Schultz 20-30-20 nutes. Last two feedings were at 3/4 strength (two within the last 2 weeks), and I just fed them today with about 1/3 strength.

pH seems to be ok - soil meter says ~6.8 or so, runoff measures about a 6.3 or so using pool test strips. I have a $130 digital ph meter, but I can't get the stupid thing to calibrate.

So is this is a nitrogen def combined with something else (maybe mag)? This seems to be a consistent problem through the flowering cycle especially. I have pulled probably 3-4 big fan leaves off from yellowing, and 6-7 of the smaller lower fan leaves. Bud production, while small (using CFLs), seems to be continuing despite whatever my issue is. I should state, that yesterday I noticed some slight yellowing around one of the main colas/buds. You can see it in the greener pic of the bud (2011-03-23_17-58-03_778.jpg)

These are at approx 4-5 weeks in 12/12.

The curling down you see in one or two of the pics is primarily from how the plant was situated in the cabinet - it was in a corner and the curvature seems to only affect leaves that were against the walls of the box, forcing them to curve.

In closing, I should state that I know I am not using top quality soil and top quality nutes - I don't need you to tell me about that :). It should still be sufficient to grow a small personal crop. I'm not a large-scale grower by ANY means, and have no aspirations to be. If this problem is nothing to worry about, then I am a-ok with that as well.

Thanks for taking a look!

 

[tokeroo]

after some further reading, I am wondering if the 20-30-20 nutes I am using could be causing a K overdose, resulting in Nitrogen and Magnesium blockage?

I have some bloodmeal I can use to add some nitrogen in after a flush w/o also introducing more P/K. Does anyone think this may be a good idea? Remember, I am around week 4-5 of flower.

 

[Seamaiden]

I say back way off the feeding, let the plant dry out a little bit, give good clean water only, then see how it's going. Don't worry too much with yellowing halfway through flower, that's sort of what's supposed to happen. Plus, if you push too much nitrogen too late into flower you could cause all sorts of funky problems, not the least of which is shitty smoke.

First things first, though--you make no mention of any sorts of bugs. I'm specifically interested in anything that looks like mosquitoes. Do you ever see anything like that around the plant? Do you ever use yellow sticky traps? If not, get some, put them near soil level near the plant, see if you catch anything.

 

[tokeroo]

Seamaiden, thank you very much for the reply.

I had a few issues with what appeared to be fungus gnats when I was in the attic. I have not seen any around the plants in months.

Should I look at getting some mosquito dunks and go ahead and dunk the plants as a precautionary measure?

Would fungus gnats cause these symptoms? I saw the post concerning some type of bug (here on RIU) that usually just lives in the roots/soil, but once crowded, they take flight. Are you thinking it could be that?

Again, thank you very much for stopping in and replying!

 

[Seamaiden]

Root aphids can cause a vast array of problems that can really get going when you're about 30 days into flower. Spectracide as a soil drench is what worked for me, flooding for 2 days at a time.

This is THCFarmer, not Rollitup. :shake
:giggle

 

[tokeroo]

Root aphids can cause a vast array of problems that can really get going when you're about 30 days into flower. Spectracide as a soil drench is what worked for me, flooding for 2 days at a time.

This is THCFarmer, not Rollitup. :shake
:giggle

That's what I get for typing fast - I meant "here OR on Rollitup" ;)

Thanks for the tip, I will give Spectracide a shot!

 

[tokeroo]

I checked the ph again today, and now it's reading super-low. Runoff was off the chart (it stops at 6.2) low, and the soil meter read anywhere from 4-5ph. I added some fast acting lime to the soil and watered them again. pH is still low, but I want to give it some time to work.

 

[tokeroo]

I suppose my next question would be: Can I use ph Up/Down safely in my water to treat this? The "fast-acting" lime has done nothing, and I applied it probably more liberally than I should have.

Something like this maybe?
http://www.amazon.com/pH-Control-Ki...KWZY/ref=sr_1_1?ie=UTF8&qid=1301235912&sr=8-1

 

[tokeroo]

while tending to the flowering plants, I noticed some bugs in the soil in my other plant. The soil was mostly dry on top, so finger-tilled it a little a saw about 20 grey-silver, skinny bugs moving all around. They move so fast it's hard to really get a good look. It looks like they *may* have wings, but don't appear to be any longer than their body if so. However, I really don't think they actually do have wings.

They did NOT fly when disturbed, but were crawling all over the loosened soil. I mashed as many as I could see.

EDIT: I have now seen some "disappear" - either I am blowing them away when I breathe or they are jumping.

I will certainly be investing in some Spectracide ASAP!

 

[HolyMunchies]

week 5 might be a little late for spectracide as I believe it stays in the plants for a bout 3 weeks or so but its close.

from your last post it would appear that you either have root aphids or fungus gnats. Impossible to really tell without a clear picture or them.

Root aphids and fungus gnats will eventually grow wings but yours may not be to that stage yet.

Spectracide will kill either of them as Sea stated. I think I payed 10 bucks for mine at wal-mart lawn and garden.

Find yourself a ph calibration kit and get your meter calibrated. Theres vids online if you search for how to do this with ph solutions. Probably 25 bucks or so.

Dont go all crazy trying to add things to fix ph problems you generally just make it worse.

 

[tokeroo]

I ordered the calibration solution for my meter. I used up the entire 4.0 bottle trying to get the thing to calibrate. I watched a few videos on how to calibrate it, did exactly as they did, and it turns itself off waiting to identify the solution. Maybe the diode is bad? It's a Hanna Instruments.

 

[Seamaiden]

If it's a new meter then the diode should not be bad, but stranger things have happened.

You're able to get it INTO calibration mode, yes? That was the difficult bit for me with my first meter. Second meter no problem, first meter, had a hell of a time figuring certain things out. My eBay seller became my best friend for a while there, he coached me through it very well, got me dialed in.

 

[tokeroo]

Yeah, it's easy to get into calibration mode, it just won't calibrate. It uses a two-solution system - a 4.01 and 7.01 solution. According to the videos (and the docs), I stick it in the first solution, wait maybe 10 seconds and it then tells me to stick it in the second solution. That should also take maybe 10 seconds.

Instead, I stick it in the first it asks for, and wait. and wait. It never really hits the ph value of the solution, but eventually asks for the other. So I remove it, rinse it with a little of the other solution and dip it in. And wait. and wait. and then it turns itself off.

I turn it on, it says it's calibrated, but if I stick it back in the calibration solution it reads all over the place. It drifts down, then up, then down, then up, etc.

I have run out of the 4.01 solution, so to try again, I need to order more. I bought it (and the solution) from Amazon. After running through all the 4.01 in one day trying to calibrate the thing, I got fed up said fuck it.

 

[Seamaiden]

There's something wrong with it if it never reads. First I'd get that diode clean, because when I was having some weird problems like that cleaning the diode (I use a cleaning solution) for some reason resolved it. I can only assume there was some sort of gunk on it that was making it go screwy.

Bummer that it's giving you fits like this just to get the thing calibrated.

 

[HolyMunchies]

I'm not familiar with the Hanna ph meter but this is a complete vid on how to do my nutradrip for reference.

http://www.youtube.com/watch?v=FKdguWXh_js

I take a full 2 min for the probe to temp compensate. Again different meters but you might see something worth trying in your next test.



here is a pdf instruction on Hanna meters in case theres something there as well.

 

[tokeroo]

Holymunchies, thank you dude! The PDF says to let it settle in the 7.0 first, then initiate the calibration. That could have been part of my issue along with apparently not having the cleaning solution. I have ordered some cleaning solution and some more 4.0. Hope to get this thing going.

thanks!

 

[IVIars]

What model Hanna? You should try leaving the probe in water for a few hours to let it saturate. I only use the 7.01 solution to calibrate.

 

[tokeroo]

What model Hanna? You should try leaving the probe in water for a few hours to let it saturate. I only use the 7.01 solution to calibrate.

98129 is the model I have

 

[IVIars]

I have the 9813-0, and was having the same problems as you. I didnt store the probe correctly (left it in the box for about a year) and the readings were all over the place. I read somewhere that you are supposed to keep the probe saturated or it wont calibrate properly. Does the ppm and ec read correctly? Mine would be fine, it was just the ph that would be off. I could be wrong, but i think the 4.01 calibration solution is incase you are using the probe for acidic tests while the 7.01 is more for alkaline? But i could be wrong.

Anyho, If saturating in water doesnt work, you might need to replace the probe. Theyre replacable for your model. And make sure your tester is warm, mine wont read if its cold

 

[Seamaiden]

Oh... shiiiittt.. yeah, you've got to keep the probe/diode wet, but NOT with distilled water. I use the 4.01 calibration solution or one of the parts of my two-part cleaning solution. I'm also pretty anal about things like calibration, make note of temperature and always use the two-point calibration method. No point in spending the money or the time, IMO, even using a probe like that if you're not going to be absolutely certain it's accurate.

IVIars, the solutions are used to ensure the meter is properly calibrated, one is neutral (7.0) and 4.01 as an acid metric. You should always, especially with that meter (it measures pH to the hundredth point) use the two-point calibration. Yours should read as long as the probes have been kept wet, clean, and properly calibrated, and will include that temperature reading. Read the calibration solution labels or look up how temp differences affect readings, even though I believe this model Hanna (the 98130) self-adjusts for temps as my readings at calibration are always spot on.


I said I'm anal about it. :giggle