Continuous yellowing from the bottom. Please help!

Hello everyone,

Thank you for reading.

I've had yellowing problems starting from the bottom, the plant is growing fine, a little slow but the bottom leaves keep drying and fall off. They start from the tip and edges and turn white to yellow and then brownish color.

I had a very hard water so i switch to RO water and it helped with the new growth looking much healthier but the bottom leaves keep dying.

I did a one bud style since the space is small and a lot of plant. So i trimmed the branches and left the fan leaves. They are now 3 weeks into flowering and i stopped trimming them 2 weeks ago.

The setup is:
two 240w LED light with 3w leds and one 300w LED light with 1w leds.
no medium and low pressure aeroponic setup. The timer is on 15min ON and 15min OFF. 2 airstones.
the water is around 22 degrees C and 25 C.
air is around 28 to 32C during the day and 24C at night.
humidity between 50 to 80%
PH is kept between 5.4 to 6.5 i let it fluctuate and it rises slowly. Adding RO water bring it back to 6.0 i don't use pH down.
There is 40L of RO water in the res and 10L of tap water. So 50L total.

The roots look healthy. They are about 60cm long. They don't touch the water in the res.

I use flora series nutes from GHE. I use a ratio of 1:1:2 (grow/micro/bloom) and 1ml/l of magnesium.

EC is around 1.1 to 1.3 EC.

I had nute burn before as the EC was up to 2.5. So i think it caused some of the yellowing.

I check the ph and EC daily and the calibration is correct also. I top up with 5L every 2 days.

The weird thing is i never see the EC going down.

Any help will be very appreciated.

I have posted some pictures. They do look small but they have a lot of nodes and about 2cm between the nodes. They were in growth for 1.5 month from clones but there growth got stunted a couple of time during growth due to overfeeding and it's now 3 weeks into flowering.

Thanks erveryone!

I don't know how much help I can be,but I see a couple of things wrong.
The first is PH should be 5.8 not floating all around.
I keep my roots covered with water.
I don't see a lot of growth from led lights but aren't they supposed to be close?
Somebody else will come along that knows more about what we are doing.
Good Luck!

nameno said:

I don't know how much help I can be,but I see a couple of things wrong.
The first is PH should be 5.8 not floating all around.

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Well no. You actually get a better transfer on nutrients if your water swings through the complete cycle. Your right though 5.8 is the point where in hydro overlaps nutrients and you get your balanced meal, so to speak. Most people do not or can not control that swing and they start seeing issues. I agree with you on the roots and wont hurt them if they are covered, just have it well aerated. Looks to me something went seriously wrong from the get go? Your 3 weeks into flowering. stocks are too small to support any weight at all, plants in general look like they were rode hard and put away wet. Do you have a bible or meters?

in my experience with hydro ph swings should only be between 5.8 and 6.2. some people like it lower about 5.5 upto about 5.9. over what time period are you letting in rise before you bring it back down?

Well i don't bring it back down the pH just stays in the right zone. Sometimes it stays at 5.8 for a couple of days. Then i add RO which bring it up to 6.0. And sometimes when i add a bit of tap water i but a little bit of ph down to 5.5 or so. If i don't do anything it will not raise above 6.2 with the RO.

I check daily and there are no sudden change at all.

Sir Ganga> what do you mean by bible or meters? The ph and EC meter are digital.

I didn't feel the need to bring the light closer since they already grew like small bushes with small space between nodes.

Also they were already in flowering alternating nodes when the light was in growth as the mother was already in pre flowering.

A couple of weeks ago the new growth went from having 5 or 6 blades to 1 single blade too. I think that was when i was overfeeding them.


This is my second growth and the last time i kind of messed up a bit but they were skinny like this as well. Could it be that there is no medium? I have fans blowing and good airflow. Although i think it's a bit too humid maybe.

Thank you for the help.

Looks like PH problem to me. But lets be honest that grow looks horrible, its almost impossible to tell what's up because they have varying stages of damage. I would start buy flushing completely, With RO get the EC to 0.8 and get that PH inline, 5.6-5.9 MAX, 6 is to high. If you lower you EC you may even find that you PH wont swing as much or as fast. New growth looks ok so you might be able to salvage if you act fast.

To be honest the Ph has been at 5.4 to 5.8 for the last 2 weeks and it doesn't swing by that much at all. I don't use PH down anymore since i switched to RO water and it only got above 6 when i added PH down. It did go down to 4.8 for a night as i added too much PH down the first time after switching to RO water. I realised it went way down the morning after.

So going down to EC 0.8 will not hurt them in flowering? Is that ratio ok 1:1:2 for grow/micro/bloom flora GHE?

Can it be that the lights are too far?

They have white powder like pollen and smelling like hashish all over the stems and on some leafs even though the buds just started developing. I think they have been shocked with a timer problem once.

Those are all laughing buddha by the way. The mother plant in soil has been experiencing the same yellowing but much less.

Also i'm concerned that the 15min ON 15 OFF timer with low pressure aeroponic might cause root problem.

More pics with the lights off.

The first pic is the mother in soil.

I've dropped the EC down to 0.8 and the Ph is already at 5.9.

They are growing well at the top but i still feel that the yellow will keep progressing to the further up. Also the middle leaves have some brown rusty spot showing as you can see on the pics above.

So you had the EC too high at first so now you want it too low to make up for it?

Just make the EC good.

It was at 2.5 3 weeks ago. I slowly dropped it down to 1.1. And now people suggested to drop it to 0.8 EC.

What is the good EC? I was hopping to see some EC drop in the res at some point to get a reference to increase or lower the EC but the EC never drops. When i top up the res it goes back to the same EC aw it was before.

What do you think?

Here are some pictures i just took. The lights just went off. You can see the rusty spots on the second picture.

Should i stop adding the magnesium as it might cause calcium lock out?

Do use Calmag? Fluctuation in PH can limit the uptake of magnesium. Just a thought.

I just add magnesium. Put the PH doesn't fluctuate anymore since i switched to RO.

reverse osmosis water added straight in will leech nutrients off your plant, be careful to at least put a little nutes in there if planning to go on a low dose that follows a bigger dose. Adding straight r/o will kind of shock em thats what i think is happening. try a complete nutrient like dyna gro or something, or just get some cal-mag and add 2-3ml/gal and work up to 5ml/gal

I never used straight RO water. The RO water is EC 0.1 or less. Right now it's at 0.8 EC using GHE flora series. I put all the details on the first post.

When i top off with pure water it's just to bring back the EC down as it raises 0.1 after 2 days of evaporation and plants drinking. Do you mean that i should top off with nutes as well?

I've been using magnesium as well around 1ml/l.

Jimdamick said:

Do use Calmag? Fluctuation in PH can limit the uptake of magnesium. Just a thought.

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I have the same problem as the OP. Yellowing from the bottom up, slow as hell growth, some sings of a mag deficiency. My ph of my soil is 7.2. I want it to be 6.5 but I was a dumbass and added dolomite lime to my FFOF and FFHF. I know I overwater too. And yes I did overfeed to top it all off. I have taco leaves, some with twists, etc. I sarted a thread asking if I can adjust my soil to a lower ph by using organic Sulfur. I have heard that mixing sulfur and dolo lime is bad for the plants. This sounds like what the OP is facing or will face soon. Things are looking ok but I need the whole plants green and growing big again.

I really don't know what to do. The yellowing keeps going. My ph has always been in check.

I'm having some kind of deficiency and i have no clue.

DEA plague