Yellowing leaves

[Istvan]

New day new issues , if anyone has idea what could be reason for this yellowing on 3 out of 4 plants pls do tell. Is it some sort deficiency,heat,light, or underwatering ?
Ps: changed light couple days ago to HPS 400w it's in 100cmx100cm(40x40 inch) tent, 50cm(20inch) above plants.

 

[Emilya Green]

Do you have a good fan to move air in there? Its hard to tell from a few pictures, but it looks like maybe a moisture and mold or mildew problem that a good oscillating fan would be able to disperse.

 

[Istvan]

Progress on the matter , I'm scared for my babies

 

[Emilya Green]

It does look more like a deficiency in these photos. I think I see signs of potassium and phosphorus depletion... are you feeding this plant? Tell us more about your grow, is that soil? If you are feeding, what product are you using and are you using their suggested feeding rate?

 

[Istvan]

It does look more like a deficiency in these photos. I think I see signs of potassium and phosphorus depletion... are you feeding this plant? Tell us more about your grow, is that soil? If you are feeding, what product are you using and are you using their suggested feeding rate?

They are fed with bio Bizz fishix+bio bloom +top max + bio heaven . Now coz of change of light (from bad LED+CFL to good 400w HPS ) , temperature increased and also perspiration so they used all water and I didn't notice, probably they run like 10h with completely dry soil ... All what you see appeared in that period.

 

[Emilya Green]

Maybe you are overfeeding and this is a lockout. You didn't say if you are using the recommended rate, but since you are giving several products, you probably are. Since I think you confirmed this is soil, are you using a feed/water/feed/water schedule, or are you feeding each time you water? Are you adjusting the pH of all of your incoming fluids, and if so, to what number? You seem to be very concerned about dry soil, and before I thought I was seeing signs of excess water. Just how often are you watering and/or feeding, and how are you determining that it is time to water?

 

[Istvan]

Maybe you are overfeeding and this is a lockout. You didn't say if you are using the recommended rate, but since you are giving several products, you probably are. Since I think you confirmed this is soil, are you using a feed/water/feed/water schedule, or are you feeding each time you water? Are you adjusting the pH of all of your incoming fluids, and if so, to what number? You seem to be very concerned about dry soil, and before I thought I was seeing signs of excess water. Just how often are you watering and/or feeding, and how are you determining that it is time to water?

I was feeding each time I watered before this happened, Let's try to paint it I ensured its weight atound 3.7 kg when watered in 5galon pot. After this event I watered untill it leaked out from pots, it resulted in about 5 kg per pot. So I think I kept it on verge of dehydration and flipped over when changed light/increased heat/perspiration. Atleast I hope that's what happened

 

[Emilya Green]

I think that feeding every time caused this problem. Let's see what f/w/f/w does. You still havent answered me about pH, so that definitely could be part of the problem too.

 

[Istvan]

I think that feeding every time caused this problem. Let's see what f/w/f/w does. You still havent answered me about pH, so that definitely could be part of the problem too.

I watering mix was always at 6.2-6.5 . Yeah Gona do water /feed schedule. How often your plants need watering in weeks 4 onward of flower? (This is my first time growing anything so 0 experience)

 

[Emilya Green]

I watering mix was always at 6.2-6.5 . Yeah Gona do water /feed schedule. How often your plants need watering in weeks 4 onward of flower? (This is my first time growing anything so 0 experience)

How often they need water depends on how strong the roots are in that 5g container. That depends on a lot of different factors. The way I do it in bloom is to lift up a corner of the container to get an idea how heavy it is. With one hand I can easily tell the difference in a full container and one that is much lighter because the plant has used up most of the water. I wait for that, and it usually takes 2-3 days between waterings for this to happen.

I am convinced now that we have talked about this that most of the problem here is simple over feeding, and when that happens, one element in the mix can lockout other elements, and that seems likely in this case. Do the f/w/f/w thing and carefully and exactly adjust your pH to 6.3 immediately before hitting the soil with any of your fluids. I wouldn't change anything else just yet, just so you can see the effects of this change. The damage you are seeing should not progress, and you should start seeing a general green up of the plant. Give it 2 or 3 watering cycles to be sure. Be patient... nothing happens immediately in the plant world.

 

[Istvan]

Thank you for fast response ! You are right It Looks greener over all already in comparison to 3 days ago.

Just one more thing, when you water after container being so light , do you water it as much it can take (untill it starts letting water out on botom) and then leave it for 2-3 days?

 

[Emilya Green]

Thank you for fast response ! You are right It Looks greener over all already in comparison to 3 days ago.

Just one more thing, when you water after container being so light , do you water it as much it can take (untill it starts letting water out on botom) and then leave it for 2-3 days?

Yes, if you water to runoff each time then that establishes a base line as to how much water the soil can hold. If you didn't water to this point you would always be guessing as to whether you gave enough, and essentially you would then be thinking for the roots and the soil, instead of letting the system decide for itself what it can handle.

 

[Mountainman80]

New day new issues , if anyone has idea what could be reason for this yellowing on 3 out of 4 plants pls do tell. Is it some sort deficiency,heat,light, or underwatering ?
Ps: changed light couple days ago to HPS 400w it's in 100cmx100cm(40x40 inch) tent, 50cm(20inch) above plants.

Try a tablespoon Epsom salt per gallon water should fix her looks to be low on potassium magnesium possible calcium also check pH if it's below 6 add teaspoon of lime to a gallon water use lightly around the base of the plsnt same with epsom salt never pour it on the stems or leaves

 

[Istvan]

Yes, if you water to runoff each time then that establishes a base line as to how much water the soil can hold. If you didn't water to this point you would always be guessing as to whether you gave enough, and essentially you would then be thinking for the roots and the soil, instead of letting the system decide for itself what it can handle.

Progress on the matter :
It looks terrible , any idea what can be done ? Just watered yesterday pure water...

 

[Emilya Green]

definitely looking worse. I'm still thinking you are watering too often.

 

[Mountainman80]

Progress on the matter :
It looks terrible , any idea what can be done ? Just watered yesterday pure water...

Have u checked the pH looks like nute lock out last stage befor she dies

 

[Istvan]

Have u checked the pH looks like nute lock out last stage befor she dies

pH of soil? Don't know how to check that, I have only pH meter for water

 

[SmokingWings]

definitely looking worse. I'm still thinking you are watering too often.

To me it looks like the plant shut down the root system as it prepares for the grand finale. That stage that some of the growers talk about where the plant is wilting and looks like it needs water. But, water does not help and neither does letting the soil dry out a bit.

If it was me I would be thinking to myself that it is time to harvest and get set up for the next grow.

 

[Emilya Green]

To me it looks like the plant shut down the root system as it prepares for the grand finale. That stage that some of the growers talk about where the plant is wilting and looks like it needs water. But, water does not help and neither does letting the soil dry out a bit.

If it was me I would be thinking to myself that it is time to harvest and get set up for the next grow.

overwatering often causes the lower roots to atrophy. That is my current theory. I want the OP to do a forensic analysis of these roots when this grow is completed, just to see what the root structure down low looks like.

 

[Istvan]

To me it looks like the plant shut down the root system as it prepares for the grand finale. That stage that some of the growers talk about where the plant is wilting and looks like it needs water. But, water does not help and neither does letting the soil dry out a bit.

If it was me I would be thinking to myself that it is time to harvest and get set up for the next grow.

This could be possible also , maybe triggered by yellow HPS light that's introduced recently