same signs, different grow...

[RuralRoute420]

just pulled all of these off the bottom of plants, it's starting to affect a few upper leaves slightly.

week 4 flower
250hps
e/f
1200ppm
6.0ph
ro water w/ 1 tsp calmag PLUS per gallon
dynagro nutes

i had this happen on last grow, but wasn't using the calmag, so i started with it on this one, and doesn't seem to have helped much.

 

[MTF-Sandman]

IMO looks like a nute burn reaching high enough levels to cause lockout. Have you ever flushed the medium? I'm guessing it's RW since you're running E/F...

 

[RuralRoute420]

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hydroton, u think 1200ppm(700) is high enough in @ start of week 4 to cause that?

 

[MTF-Sandman]

Hmmm...dunno. It's been a long time since I've used Dynagrow.

One of the main reasons I was thinking nute OD/lockout was the burnt tips and clawed leaves.

What's your ventilation situation, RH% and temps? If they're transpiring lots of moisture then it can cause them to uptake more nutrients than if they are in an ideal environment. (ie. high temps, low humidity and lots of airflow will cause increased nute solution uptake).

One way to tell is monitor the ppm of the res...if it gets higher (just before topping it off) then it's a nute OD or uptake problem (lockout).

Is the PH fairly stable?

 

[RuralRoute420]

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it's just a closet grow, ventilation are through fans and circulation through open house....temps @ top of budz are no higher than 75'Fday, 68'F@night. i let the ph fall between 5-6, whatever is easiest.


the ppm stays fairly stable (15-18gallons in rez), drops 100 or so every few days. i hate dumping the rez already, but am willing to do it if it needs done.

 

[RuralRoute420]

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would adding 5 gallon of plain RO, and ph the rez, and drop the ppm back down to 1000(700) or lower help out any????


i've been suggested that my ppm might be too high for the low light (250w)...

 

[MTF-Sandman]

Sounds like a good starting point. Maybe add straight RO for 4 or 5 days and see how the new growth reacts to it.

 

[RuralRoute420]

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can you empty 1/2 the rez, retop, and set your numbers from there? or does one have to empty the entire contents?

 

[MTF-Sandman]

You can, but diagnosing things will be alot simpler with a complete res change. I'd imagine with only a 250w that the res isn't that big anyhow, so it's really not going to cost you much more to do a complete change.

The problem with only doing a half change is (especially with nute issues) that you might still have a toxic level of a certain element while the other elements are extremely low...thus giving you a low ppm reading but still possibly having a nute OD. I'm not saying that it will happen like that, but it's a definite possibility.

IMO - just do a full res swap. I know it sucks throwing out those nutes, but sometimes it's just cheaper to cut your losses and save the time hassling with it....besides surely some yard plants will be able to use the nutes. I've got some massive orange trees from where I dump my nutes.

 

[killa-bud]

i thought it was common that leaves turn yellow when they flower?

 

[MTF-Sandman]

i thought it was common that leaves turn yellow when they flower?

It is common for them to yellow later in flowering, but those are not yellowed leaves from allowing the plants to use up all the available nutes. Here is a pic of what you're thinking of...

 

[RuralRoute420]

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here's what they are off of. now, i know you aren't suppose to flower 2 strains with one rez, but i did anyways, due to discontinueing these strains, it's all i had to work with. also, playing around with what will work and what won't with system. going to change out rez (15 gallons) in next 2 days. and set ppm@900 or lower and go from there. since adding 1tsp/gallon of calmag to RO water raises the ppm, should the actual ppm be 1100 or 900? trying to grasp the additive part of this....

oh yeah, there is also a 175MH in there with the 250hps.

 

[MTF-Sandman]

Don't sweat running 2 strains off 1 res...I'm running 4 different strains right now on a single res. As long as they have similar nute requirements they'll be fine....or you can just find the happy middle ground between the 2 and go from there.

PPM is PPM...no matter what's causing it to raise. So consider that Cal-Mag as part of it. I would try running them at ~900ppm (including everything) and work up from there as they allow you to except for the last week or two, then I'd let the ppm slowly decline and just add straight RO until you chop them. It's kind of a compromise between flushing and feeding all the way to the end that seems to work pretty well for me.

 

[RuralRoute420]

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much thanks MTF, you've been a great help. switched out to fresh 10 gallon rez starting back @ 700, we will go from there.

 

[RuralRoute420]

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they've been sucking the water down, and the ppm rises slightly to with it. middle of week 5, should i just stay at 700 till the ppm lowers or, back off the nutes slightly?

 

[guest3854]

If they are sucking tha water down , but tha ppm is rising , I would believe that you have a potassium toxicity problem . Your nute ppm should be goin down with water usage , not up . Since your so close to harvest , I would flush that dog shit outta em , using clearex or tha like and then go easy . You only have 3 weeks to go so your at tha home stretch , just try to correct as best you can within this time . Hope this helps .

Steel

 

[MTF-Sandman]

If the PPM is still rising, then they either have a lockout from nutes/PH or the feeding strength is too high. Sounds like a good time to flush them with 1/4-1/2 strength nutes to me...

 

[RuralRoute420]

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ok, so i can just addback plain RO water till my ppm reaches 400 then? i'm feeling so green right now, but i'll put pride aside and ask the simple questions till i get this straight.



nobody has asked about ph though: i was running it around 5, but now am around 5.5

 

[MTF-Sandman]

If the ppm is just slowly rising, then adjusting the PH up to around 5.8-5.9 and lowering the nute levels a little should take care of them.

Under ideal circumstances, you'll want the PPM to stay the same as water decreases then just top off the res with new solution at the original PPM. This would mean that the plants are eating at drinking at the same ratio and that you are feeding them correct nute levels without building up higher levels of unused nutes.

It might help to add a catalyst like Liquid Karma to increase the metabolism of the plant as well...that could allow the plant to use the nutes at the levels they are currently getting...

 

[RuralRoute420]

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10-4. they're still growing good, don't get me wrong. new growth shows no signs, but slight slight tip burn....dropping ppm lower. adjusting ph to 6. or try too.