yellow/brown crispy mature leaves, and curling young leaves

[kooshitsu]

hello gang,
i'm a totally new grower and new to this site. This is my first post so ill try to be as precise as possible.

i'm growning in a hydroponics flood and drain system, 4 buckets with a 40 liter main tank, the light is on a 16 hour schedule and the water comes on for about 5 min ever 3 hours, (enough to fill the bucket) and it takes about...2 min for the bucket to drain. And 4 additional hempy buckets.

two hempy buckets have LA con, and the other two have the same as the hydro system. (skunk 1) Everything in the hempy buckets is doing fantastic, aside from my stupid ass splashing water on them and sticking them back under the light to get burnt. (but i only did it once) :o)

My problem is coming from the hydro system plants. Im not sure what it is, i've had a look around and the thing that seems to be the closest is nute burn, but i'd like some expert opinions on that diagnosis, as my plants don't seem to look exactly like most nute burn pics, maybe it's a combination of things. uh (sigh)

The problem is that the bottom most leaves, (the oldest ones) seem to be turning a bit sickly yellow, then getting brown spots and getting REAL crispy, if you touch them they break and almost turn to dust. the top newest leaves are fine but the middle leaves seem to be now curling downward. The main vein in the middle of the leaf has become quite rigid in it's downward turn.

I'm about 4 week in using aqua veg nutes.
EC, was at 8 (same as the hempy buckets)
Ph is at 5.5/5.8 it ran for about a week and this started. once it started i flushed for 24 hours and they seem to perk up so i put more nutes in at EC 5. and it now seem to be even worse. so at the moment i've just running pure Phed 5.5 water through till one of you fine knowledgeable folk hopefully can help me.

 

[likeakite]

Not terrible looking. They look like young plants. Could those lower leaves have been damaged thru recent transplanting? If this condition is spreading upward we need to figure this out.

You say the EC is at 5? I hope you meant .5

Your PH should be allowed to fluctuate between 5.5 and 6.5. If you check a chart for PH, you will see that some elements are more availabe at a slightly higher PH while other elements are more available to the plants at a lower PH.

Also noticed just a bit of heat stress on a couple leaves, so watch the temps.

Not that bad, all in all. If the top growth is growing faster than the lower growth is dying, youre ahead of the game, sort of. Now you just need to figure out whats stressing them. I'd bet if you fluctuate the PH, it will go a long ways toward their health.

Remember that damaged leaves will not recover. They will likely die and dry over the next couple weeks, so just write those off and concentrate on keeping the healthy leaves green and happy. Grow em' tall.

 

[negative 1]

i would also say up your ph to 5.8 and let the rez drift it between that and 6.4. this way all nutes are available at different ph levels. seems to me that you may be experiencing a lockout of nutrients more than too much. just my opinion though. i would try a ec of 1.0 the yellowing paleness of the leaves in the third from bottom picture is looking like not enough nitrogen. also it starting form the bttom and progressing upwards is a sign that the plant is kinda in a way eating itself from any reserves of food it has stored.

 

[JayBee]

welcome on the board kooshit, glad you made it. negative one is totally correct, get that ec up!

 

[highroller]

You know, I hate to harp on this, but if you look down the list of threads in the infirmary you will see this same thing happening to many grows. Every summer when it get hot and humid i see a shitload of these threads. I'm firmly convinced 90% of them are a fungal disease exacerbated by the high temps and higher humidity. I don't think it has anything at all to do with ph or nutes.
every summer I ask myself why I grow indoors without climate control like AC. Results can be so dismal only to rebound once the cooler fall and winter temps and lower humidity prevail.

 

[kekoa-30]

aloha kooshitsu,
i am going through the same problum at this very moment ,at first i taught over fert's but now i it really looks like a fungi,problum i am using soil so i am repoting all of the infected plants an going to treat with some fungi spray ,i will post the result's if it solves the problum, an if i find an answer i will post the info ,aloha kekoa-30

 

[shdowlkr]

You know, I hate to harp on this, but if you look down the list of threads in the infirmary you will see this same thing happening to many grows. Every summer when it get hot and humid i see a shitload of these threads. I'm firmly convinced 90% of them are a fungal disease exacerbated by the high temps and higher humidity. I don't think it has anything at all to do with ph or nutes.
every summer I ask myself why I grow indoors without climate control like AC. Results can be so dismal only to rebound once the cooler fall and winter temps and lower humidity prevail.

True and reservoir temperatures in hydro are very important. anything over 74 F spells trouble fast.

What is your watering frequency on the hydro pots?

what about grow room temps and RH?

 

[kooshitsu]

the saga continues

hello again all,
thanks for all the great advice. Just to follow up....after reading the remarks post here i've gone and upped the EC to 1.0 the general consensus was that it was NOT nute burn but more a lock out / not enough food problem.
So i pruned the dying leaves off, emptied the tank completely, and started over. Mixed "A" into water poured that into the tank, let it sit and stir a bit ( i have a pump in the tank that just stirs the water continuously) then came back and added a diluted solution of "B". Last night when i was doing all this the EC was 1.0. Upon checking this morning i see it's dropped to .8, we started with a pH of 5.5 and again over night its gone up to 6.0ish, so i'll that go a bit higher before i ph it again. you guys reckon let it range between 5.5 and 6.4. so i'll give that a try. The only other things i did last night was add a bubbler to airrate the water. I'll send pics in a few days so you guys can check the progress with me. :o)
Also during the night it seems to have shot off two new decks of leaves, (healthy ones) so it must have liked something, however now the "teen" leaves are curling under quite drastically. But they are NOT yellowing or anything, just curling under, like a claw.
The two LA's and two smaller SK1's in the hempy buckets are still doing fine. I've also uped the EC in their feed to 1.0 and they seem to happy with that.

thanks again for everyones help. i'll be posting more of the grow just so everyone can see how it's going and help me maybe spot any potential problems along the way.

 

[kooshitsu]

i think my problem may be more with UNDER feeding. :o) So i've tried uping the EC and letting the pH drift to 6.4 from 5.5 (or so i've been told above) i'll give that a try and also report back. thanks for the post.

cheers

 

[JayBee]

Someone else posted this a while ago, but always find it helpful:
Basic cheat sheet:
Ec goes up, PH goes down=plants require less nutes.
Ec goes down, PH goes up=Plants require more nutes
Ec stable, PH goes up=Equilibrium=Good thing.

 

[kooshitsu]

ok, now i've got some pics to put up as well, and it's getting stranger.

Again i'd like to thank all the guys that posted back, good advise all. With that said i've been uping the Ec gradually and letting the pH drift a bit. But a strange thing happened. We topped up the nutes so it was about 1.1 and the pH was 5.5 everything look like it was going to get better. but alas, i wake up the next morning and check the babies and the pH and dropped to like 4.3 (what the hell is that all about) and the Ec went down to 8. How is something like that possible? So anyway we took care of it added some water to bring the pH back to 5.5 and added some nutes to get it back up but maybe the strangest thing is ONE plant is getting better and bigger. The other three seem to either be getting worse or not doing much at all.

So today i flushed the system, poured 2 buckets of fresh water into each growing bucket, let that drain and then poured in 4 buckets into the reservoir and then pumped it out. Mixed up some more nutes and got the Ec to 1.4 and the pH was about 5.8 straight out of the tap so i figured i'd leave it for a day and then check it tomorrow and maybe pH it if it's gone up much. I figure if i pH it now it may drop like it did before, my thinking is that something must have evaporated out of the water and made it drop like that because we'd pHed to 5.5 and when what ever it was evaporated (let's say for instance it was the chlorine) maybe it will evaporate tonight and i can pH the water and maybe not have that drastic swing.

The room is a pretty steady as far as environment, the temp is steady between 25-27c the humidity is between 30-50% and water temp is about 24-25c.

So what do you pros think?

 

[JayBee]

how far is the light from top of the plants?

 

[shdowlkr]

newer growth looks 'ok' you do have a Mg issue coming on. Possibly brought on by the low PH you encountered... also, do you have a way to check/calibrate your PH pen?

 

[highroller]

Have you tried an application of SM90 or Neem to the affected areas?

 

[blueleaf]

i had similar symptoms showing outdoors,
in my case im sure it was under-feeding.
i hope the best for your little ones :)

 

[kooshitsu]

the light is about 3 feet away from the tops of the plants.

 

[kooshitsu]

yes, it's a two point calibration and i did it again just a week to week and a half ago. it's really strange. (what's going on not the calibration of the pen)

 

[kooshitsu]

this is the one thing i have not tried yet.

 

[JayBee]

be very careful if spraying the leaves with sm-90, might be better trying to add it to resv first.

i was thinking that light might be too close but three feet is actually pretty far away. With that air cooled hood you can get it down another foot so it is 20-24 inches away from top of plants.

i think best thing to do is keep an eye on ph, if it drops down to 4 again something strange is up, maybe the cheap clay rocks? otherwise keep working the ec up, watch air temp and humidity (aim for 60% RH) and i think they will be ok. i think after being so underfed they maybe going through little shock but i am hoping in another week with correct feeding they will start to correct themselves.

ANyone else think it is possible that this will correct itself once they get used to full feeding?

JayBee

 

[shdowlkr]

When all else is "right" look to the roots for problems...

Nutrient solution temps? high temps can cause pythium and that will cause severe issues and PH problems.

jaybee, if lack of food is the case, they should jump right to the increased dosage but the plants do not look underfed. If anything (to me) it appears as a macro nutrient issue, which points to either the PH issues or root issues.


Is the new growth coming in ok? is the older growth staying the same? if so, you've hit the right combination and its time to monitor PPM readings to tailor the food to the plants.