Very bare plants mid flowering: All leaves yellow/bleaching!! Help.

Hey everyone.

i've got some plants of saliva dominant strength and they are a bit over halfway in the flowering stage. It's the 8th week since i switched to 12/12. I switched them early in veg (after 4/5 weeks) as i wanted to keep them short.

The leaves have been bleaching for a little while now. Everywhere on the plants. And they have no more fan leaves... (my share mate cut them...)

I'm using some organic nuts from VG "Pachamama" following the schedule and also checking EC. (also putting some booster and sugar babe as per the schedule).

They are in a low pressure aero system. With a separated reservoir and massive root chamber. Everything is getting wet nicely. I was watering 15min ON 45min OFF but then switched to 15min ON 1h15 OFF but it seem to have worsen. I just switched back to 15min ON 30min OFF today.

I'm adding some H2O2 daily in small doses, changing the res water every 2 weeks, controlling Ph and EC twice a day. The ph is kept between 5.5 to 6.3. I usually set it to 5.8 it drifts up to 6.2 the next day. EC is around 1.9 and i add water every day as it keeps rising as the level drops. (increases 0.2 a day).

It has been great during vegging. Then i went overseas for a month and my share mate was taking care of the plants. He left the watering fully ON for 24h twice when changing res... Which did some harm to the leafs. Then he decided to trim all fan leaves (face palm...). Then the yellowing kept on going. I trimmed some of the very dead leafs but now i don't even dare to take anything of it as it's so bare...

Then the yellowing kept on going. Is it just because of the flowering? The buds seems quite small but it's sativa and still a bit to go. The leafs are yellowing at the top and the bottom. Shortly after they grow.

The plants are under LED:

1x 280w with 1w leds
2x 240w with 3w leds with Lenses.

The leds are about 40cm away. Could it be the cause of this?

There are fans circulating air inside the room, I have extraction too. Humidity is always around 60 to 75%.
Room temp is 68F/20C at night and 75F/24C during the day.
Root zone is at 68F/20C
Water temp is around 64F/18C to 68F/20C. (I have 2 air stones and 30L of water in the res.)

It seems to keep yellowing all the time. I wonder if they will survive or even yield anything. There are a lot of small bud sites growing slowly and very smelly already!!

I have attached pics. I've read a lot and couldn't find many people with plants looking that bad lol.

I have a new batch of clone growing. This was my first grow ever. Next time will be better

Thanks everyone for your help!





Strawberry cough:







Laughing Buddha:








Blue Cheese:

Do you guys think it's normal that they yellow that much as it's flowering and they have no more big fan leaves to dry off?

Could it be nute burn?

I'm also concerned that the buds look small...

Any help would be much appreciated, i've changed many parameters but it didn't do anything...

want to help but cant see your pics, just takes me to a new page and says "Invalid Attachment specified. If you followed a valid link, please notify the administrator"

It's weird the links work on my computer. I've reuploaded them in smaller size. It seems to work. See edited top post. Cheers guys!

Also on the pics, i've turned off 2 leds and used strong flash so it looks like with normal light pretty much.

K there we go I can see them now.

OK looks like nute burn/pH lockout. My theory is that the concentration you have been feeding them for aero was fine for your short exposures (15 min), but when soaked in that solution (24hrs), it was too much nute for them. This may have caused the damage you are seeing. Also note that the constant oxygenation from the misters spraying the solution over and over again, (if your system is recirculating) will change pH- not to mention the level of evaporation that goes on with that much spraying (changes EC and pH).

It would also be a good idea to take a temperature reading right at the tops, to see if the LEDs are getting the plant too hot- but looking at the pattern of necrosis, I doubt that this is the issue.

As you resume the feeding schedule, you need to back off the nutrient concentration. Now that the plants have less leaf mass from the trauma, they are using less nutrient, and your normal solution for this stage may be too strong. This may be the reason for the continued necrosis.

Looks like these plants have been starved before you must have gotten them and they lack extremely in nutrients and water supply and probably got to much light at the same time and burnt up, creating smaller buds and that defect.

Ok guys. Thanks for the input!

I'm looking really carefully after my plants and I raised the EC has the plant grew and it was fine before. I was at 1.5 EC in late veg and now at 1.8 EC with the bloom nutes.

I can assure you that my EC never raises above 2.1 and my PH is always kept under ~6.2. Water evaporates and i check the level everyday and add water then balance PH.

Even when topping the water, the EC always raises about 0.1 to 0.2 in 24h. And the PH raises from 5.8 to 6.1 in 24h.

I was wondering also if the fast that they had less leaves meant that they would need less nutes.

How much should i back off the nutriments? Down to 1.3 EC? or even lower?

The temperature is really not hot at all at the top you are right. The last week they were running on 15 ON and 1h15 OFF and i don't think it did them good.

Before i left them to my mate after 2 weeks flo, the plants were looking greats with nice green color and nice leaves all over...

Here look at this site and check out the Phosphorus (P) deficiency:
Figure 11 is severe phosphorus (P) deficiency during flowering. Fan leaves are dark green or red/purple, and may turn yellow. Leaves may curl under, go brown and die. Small-formed buds are another main symptom.

Your plants look almost identical and theres alot more information

Yes it've seen this but i thought that since i'm using Ph Down which is Phosphoric acid for flowering it would not likely be the case since i'm adding about 5ml a day to bring back the Ph down. Or the Ph would raise even more quickly wouldn't it?

If you are having deficiencies you have PH problems. You need to start calibrating your PH pen regularily, and if it does not calibrate GET A NEW ONE! If you are using a hydroponic fertilizer then you should be OK. If you pen is not calibrated, you get things like this happening.

If anything it looks like a massive magnesium deficiency. Do you have clones? I would write off this crop and start a new one. You will not get much from this one, it is too far gone. If you have problems like this, ask as soon as you see problems, not when it is too late.

Dont give up, just chalk it up as a learning experience.

Thank for the reply.

The pen is new. I have been calibrating my ph pen every month. And the pH only drifts 0.1. i've just calibrated it again and it's fine.

I can assure you that the pH never ever went above 6.5 and below 5.2 as a record high and record low with this grow.

The fertilizer is for hydro yes.

What could be causing this Mg def?
Thanks

My plants looked exactly the same and im running LEDs as well turned down the heat and raised the lights up a bit and one survived but recovered!

defonest said:

My plants looked exactly the same and im running LEDs as well turned down the heat and raised the lights up a bit and one survived but recovered!

Click to expand...

What kind of leds were you using? And how high did you raise them?

Could it be photoinhibition? It's about 700w leds above 7 small plants with very little foliage...

looks like a nute lockout .. and greenthumbsucker just read my mind so listen to him

1w-3w leds should do the job of sustaining foliage.. i have a successful veg from 2 45w LED panels. not sure about flowering, i upgraded to 500w for that.... then i realized to be simple, just use a HPS and i could have saved $1000

I got the 90watt bloomboss and I had only a small pc fan to cool my grow cab when it happened and when I got a thermometer I saw the cab was about 91degF so I got bigger fans 120mm and It brought temps down to 72-81deg raised the light 1foot up and the plants were recovering but 3 out of 4 were already too damaged and weren't letting out new shoots so they ended up not making it.. Now that the plant recovered i moved the light down to about 7inches and they are doing great! DWC by the way...

i dont know how you got that hot in the cab with LEDs. I remember running my LED in my mylar tent, it got up to 82F thats about it. i had no problem with my plants touching the lights even if i forgot to raise them for a day. i used a scythe ultrakaze fan that did 135cfms, shit was louder than a duct fan that i use now. just keep the lights 1-2 inches from your plants

The heat is definitely not an issue. But the leaves are really bleached. I read that it can be caused by photo inhibition. I've left only 1x 240 3w panel for now to see if it makes a difference.

The lights were a little higher than 1ft above the plants.

If it's a nute lockout what could be the cause? everything has been kept in check closely.

bleached leaves from the top down is a sign of immobile deficiency. such as sulfur, iron... etc just flush your medium with correctly pHed water. make sure you adequately flush (pouring a cup of water down doesnt count). feed them 1/4 strength - 1/2 strength nutrient and B1

oh yeah, i forgot, MAKE SURE you calibrate your pH meter before you do any of this... more than likely, you forgot to calibrate your Ph meter and it drifted out of calibration...

I'm in Hydro recirculating in a tank. Should i flush the system with clean pHed water for 24h?

Do you mean 1/4 strength nutes or 1/2 strength nut if using B1?