Rust leading to yellowing

[Poezebeest]

Hello everyone,

I've been having troubles with my plants, starting 2 weeks ago, and I can't find a solution. Since the Dutch forums are not as active like they used to be, I've decided to look for help here. The only answers I got there are magnesium deficiency, starting with CalMag too late and stopped with grow nutrients a bit too soon (I switched to bloom nutrients after 2nd week 12/12)

My problem starts with little rusty spots on the nerves, which then turn to yellow leaves with brown spots and finally wither away. This happened to the fanleaves in the middle of the plant.

Here some basic info:

Strain: Critical (Zamnesia) x4

Stage: about to finish 5th week on 12/12, counting last 3 weeks as bloom

They are in soil, in 11liter smartpots, in a 80x80cm tent

Light: Mars Hydro FC-E 3000 (300W)

Climate: 20-23°C / RH 50-60%

Using tap water (hard), room-temperature, brought to ph 6.3-6.5 after adding nutrients

Bugs: none sighted since start

Nutrients used/to use: Plagron grow, bloom, enzymes and green sensation. Biobizz CalMag

When the problem started I was using 2.5ml/liter bloom (half of maximum), 1ml/liter enzymes every day. Also the minimum weekly amount of CalMag for 3 weeks.
To combat to problem I gave a little more bloom nutrients (3-3.5ml/liter) combined with a small daily dose of CalMag (1/3th of the weekly maximum).
I give them water everyday. Over the past 2 weeks I only gave them water without anything (but correct ph) twice.

At first it seemed to have slowed down the problem. But since a few days, the problem has worsened again and now are affecting the sugar leaves.

I hope any of you guys have some advise.

Here some pictures. There first 6 pictures are the progress it made for nearly a week, starting 2 weeks ago. The last 4 are of how things are going now.

 

[Fenderbender]

Welkom Poezebeest,
I'm sure advice will be popping in soon, I'm very bad at reading tea leaves and have a some similar looking leaves going on.
I'm just wondering where did you get the watering daily in soil from? I mean quite impressive that they got to this stage without them being super droopy.

 

[Roy Growin]

Hello - looks a lot like a Potassium deficiency
Are you using any PK or other flower boosters?

 

[Sparkey224]

I wouldn't water everyday in soil my friend, if it was me. Your leaves definitely dont look like you are watering that much as mentioned above.
I would always mix cal/mag first in the water, then add the rest of the nutrients to the bucket.
If the soil stays saturated all the time you will run into more deficiencies.

 

[Emilya Green]

Hi... I will give a stab at this. First, I believe your original advice that this was a magnesium problem was correct. Supplementing with calmag, up to its maximum dosage with each watering should have reversed the problem. But then you started overthinking. The water only for an extended time is what you are seeing now... you have been starving your plants at a critical point. Get back to the recommended feedings, at 6.3 pH, and use a f/w/f/w pattern, also adjusting your plain water waterings to 6.3 and I think they will green back up for a nice finish.

 

[Poezebeest]

@Fenderbender I try not to give too much water, but I may have given too much on occasion. I usually give 2-3 liters a day, divided over the 4 plants.
I pick up the pot, to feel if they are heavy or not. The soil is usually fairly dry at the top, a bit moist deeper inside.
I've never given water with something worth calling a runoff. At most a few drops coming out of sides of the smartpot.
I'll be buying tensiometers for next round.

@Roy Growin I've started with green sensation yesterday, half dose yesterday and 1/3th today. Combined with half the maximum dose of bloom nutrients.

@Emilya The product itself advises to give 0.8-1.2ml/liter a week in case of deficiency (daily when using RO or soft water). I have given 0.4ml/liter daily for the past 2 weeks now (except 2 times), which is already more than advised. Though, they might need more than advised under LED.

With f/w/f/w pattern, I suppose you mean alternating between a day with maximum nutrients and a day just water?

 

[Poezebeest]

@GainesvilleGreen That is what I worry about, the deficiency being related to the watering habit. But it's been 16 days since I last skipped a day. Since 12/12, I only skipped 4 times.

 

[Emilya Green]

@Emilya The product itself advises to give 0.8-1.2ml/liter a week in case of deficiency (daily when using RO or soft water). I have given 0.4ml/liter daily for the past 2 weeks now (except 2 times), which is already more than advised. Though, they might need more than advised under LED.

With f/w/f/w pattern, I suppose you mean alternating between a day with maximum nutrients and a day just water?

Yes, exactly. Soil is designed to be able to temporarily store your nutes for a second pass. The water only pass picks up those nutrients and cleans out the soil each time. If you have been giving feed every time, you could have used a proper flush, which is defined by running 3x the volume of your container through the soil in one sitting, producing lots of runoff. This would clear out the salts left behind by your nutes and allowed for a better ability to feed your plants. You are not using this tool called soil, correctly.

Don't just go by the instructions on the calmag... these are very needy plants and often, especially when using LED or filtered water, they need extra magnesium. Now that you have been starving your plants for a bit, they also are now short on calcium as noted by the damage on your leaves. All I can do is advise you to run the maximum dosage on your calmag... it is up to you to follow that advice or not. You did come here for answers though, true? We are not trying to mislead you.

You also need some work in the watering department. Now that you are in bloom, you are not hurting anything by watering so often, but earlier in veg, if you were watering like this you didn't do your roots any favors. Before you do another run, I would like it if you checked out my writings on the proper way to water a potted plant... the link is in my signature. If you learn how to work the wet/dry cycle to your advantage, the next time you are at this stage, you will have much stronger plants.

Also, you need to be less timid with your nutes. Again, you came looking for answers and you are not liking what you hear. The manufacturers recommend a certain amount of nutes for a reason. You going with a third of that, again, is not doing your plants any favors.

So its several things... and each grow you will get a little better at dialing all this in. This time you are going to get a nice harvest, and congratulations... but it won't be as pretty as you would like. Dial in all these things we are telling you next time, and you will have a completely different experience.

 

[Poezebeest]

@Emilya I hope I didn't give you the impression that I don't like what I hear. I just want to make sure we understand each other correctly, so I don't screw it up even more. I was trying to be careful with the booster and work my way up to the maximum dose.

No worries, I didn't water them everyday in the grow phase. I only started doing around the time the lights went on 12/12.

 

[Emilya Green]

@Emilya I hope I didn't give you the impression that I don't like what I hear. I just want to make sure we understand each other correctly, so I don't screw it up even more. I was trying to be careful with the booster and work my way up to the maximum dose.

No worries, I didn't water them everyday in the grow phase. I only started doing around the time the lights went on 12/12.

No worries here... I had to get to know you a bit and really see this problem completely, and I tend to push a bit to get where we need to be. Thank you for not getting angry, but seeing that I really am trying to help.

That is great news that you water differently in veg! You are good as far as the watering goes then and I don't see that as part of this problem as long as you adjust to f/w/f/w and start using your potting soil in the way it was designed to be used.

The need to periodically flush out the salt is why I gave up on synthetic nutes and went with a much more organically based grow system, and while gardeners are using chelated nutes, the left over salt is a problem that needs to be dealt with. Some people do periodic 3x the container flushes and others water to 20% runoff to try to wash the salts away, but you are doing neither. But then, we also have to consider that you have been giving only water for a while, so that doesn't build up salt... and you have been giving 1/3 nutes, and that also doesn't build up salt in any alarming amount... so I don't think your problem is a salt lockout. I think you have been simply starving your plants.

If you start giving full nutes, you will also be giving more calcium and magnesium along with it. You need to get to the baseline to see what happens when you give the nutes exactly as recommended, and then it will be time to reevaluate. I think that most of your problems will go away with proper feeding. All my previous advice to give max calmag or flush is now superseded by the knowledge as to how little you have been feeding. The KISS principle applies... the most obvious solution is probably the correct one.

 

[Emilya Green]

Why are you thinking about boosters, when you aren't considering giving full nutes? This makes me shake my head... it does not compute. Did someone advise you to do this?

 

[Sparkey224]

Im with Emilya on staying away from boosters. Little bit too much and your plants are going to slap you.
I dont mess with them really, npk is all jacked up. Just a good ole 3 part nutrient system and a good carbohydrate is all you need for salts imo

 

[Poezebeest]

Thx for the replies.
I will give more nutrients next watering and hold back on the booster.
I have never flushed because I'm worried my soil would be soaked for too long, even though I have considered it.

Noone advised me about giving booster when not giving full nutrients. I've seen grow journals where people use booster and/or pk 13/14 while not maxed out on other nutrients and the plants seemed to be doing fine. I also went for a low dose because I've heard booster might accelerate leaves getting yellow.

After work, I'll be reading your post in your signature about watering.

 

[SmokingWings]

I wouldn't water everyday in soil my friend, if it was me.

It depends on how big the container of soil is, though. If using some of the 3 to 5 gallon containers, many of which do not hold 3 to 5 gallons of soil, then it does become necessary to water every day. When these plants start to flower they are larger, as in having more green or mass, than when they were in a pure vegetative growing stage.

All the growing buds are demanding water. They are green, have chlorophyll, photosynthesis is continuing, and all the green is still transpiring water.

Plus I am a firm believer that some, maybe all of the problems, that growers see in their plants during flowering, are made worse by there not enough water available for that plant and for the micro-organisms in the soil.

Though, it does not mean that it makes it OK to just dump all kinds of water on the soil when it is not needed. Have to be able to read the plant and the soil.

 

[Sparkey224]

It depends on how big the container of soil is, though. If using some of the 3 to 5 gallon containers, many of which do not hold 3 to 5 gallons of soil, then it does become necessary to water every day. When these plants start to flower they are larger, as in having more green or mass, than when they were in a pure vegetative growing stage.

All the growing buds are demanding water. They are green, have chlorophyll, photosynthesis is continuing, and all the green is still transpiring water.

Plus I am a firm believer that some, maybe all of the problems, that growers see in their plants during flowering, are made worse by there not enough water available for that plant and for the micro-organisms in the soil.

Though, it does not mean that it makes it OK to just dump all kinds of water on the soil when it is not needed. Have to be able to read the plant and the soil.

I totally agree with you. For me to think about watering plants daily isn't healthy, especially in soil. (depending pot size and plant size).
If thats the case grab some coco, especially since hes using salts.

ive seen great looking plants too from using foxfarm soil with salts.
Like you said reading your girls and understanding them is everything.
Thanks for clearing that up for me my friend

 

[Poezebeest]

I bought a Fertometer, which is supposed to measure the level of nutrients in the soil. It is what it is, an indicator and not by any means something to accurately measure the EC of soil. I've tried this device and it told me the soil of every plant is low on nutrients, despite being watered with a full dose of nutrient earlier this day.

Nutrients aside, I do think my plant have some wet feet right now. Not necessarily from daily watering, but giving too much at once some days ago. My pots aren't very big, only 11 liter (2.9 US gallon if converter is correct?) and are smartpots. I experience the soil dries up rather quick on the sides while the core and bottom are still moist. According to a moist meter, even on the wet side at the bottom.

@Emilya If I want to follow your f/w/f/w advise, how would you suggest I could start with it considering my soil seems depleted and somewhat too wet? If I want to skip a day to let everything dry up some more, is it still advisable to put in a 'just water day' the day after?

I bought a bottle of Plagron CalMag today, same brand as all my other nutrients. Here is advised to use daily, unlike the one I'm using now. Would it be safe to switch?

 

[Emilya Green]

I bought a Fertometer, which is supposed to measure the level of nutrients in the soil. It is what it is, an indicator and not by any means something to accurately measure the EC of soil. I've tried this device and it told me the soil of every plant is low on nutrients, despite being watered with a full dose of nutrient earlier this day.

Nutrients aside, I do think my plant have some wet feet right now. Not necessarily from daily watering, but giving too much at once some days ago. My pots aren't very big, only 11 liter (2.9 US gallon if converter is correct?) and are smartpots. I experience the soil dries up rather quick on the sides while the core and bottom are still moist. According to a moist meter, even on the wet side at the bottom.

@Emilya If I want to follow your f/w/f/w advise, how would you suggest I could start with it considering my soil seems depleted and somewhat too wet? If I want to skip a day to let everything dry up some more, is it still advisable to put in a 'just water day' the day after?

I bought a bottle of Plagron CalMag today, same brand as all my other nutrients. Here is advised to use daily, unlike the one I'm using now. Would it be safe to switch?

Nothing should be used daily... do not follow those directions!

You don't know that your soil is depleted, but that shouldn't even be on your radar screen since you are using bottled nutes. Your soil is simply being used as a plant holder and it wouldn't matter if it was depleted of nutes. Why would it be depleted anyway... did you buy it used? Of course you didn't, but I wanted to make this point. If half a grow depletes your soil of all of its goodness, it was not a good soil in the first place.

I hate to say this to you... but that indicator you bought is worthless. If you are really concerned about your soil's content, send it somewhere for a complete analysis, in a lab.

Smart pots do retain a moisture core, in the center of that container, and attached to the bottom. If there is water there, your plant is not suffering. I don't care if it takes 3 days or 7 days to drain that container, stick to the f/w/f/w schedule. It is only in your imagination that the plant can't do without nutrients between waterings.

Lastly, here is a truism for you to ponder for this evening... You can not overwater a plant by giving too much water in one session, or even with a 3x the container sized flush, because the soil is designed to only be able to hold a certain amount of water before the rest runs out as runoff. The ONLY way to overwater this plant is by watering too often... by not waiting for the soil at the bottom and the core to run out.

 

[Poezebeest]

I meant every watering, my bad.

When you add nutrients into the soil and the plant uses them, wouldn't that deplete the soil from said nutrients? A low EC means low available nutrients, no? Sorry for being confused about this.

I don't need to ponder about the overwatering, that I do understand.

It just seemed counterintuitive skipping food after you said I was starving my plants and weird to follow the manufacturer's instructions about the amount of nutrients given but not the instructions about giving it every watering.

 

[Emilya Green]

But, you are feeding if you use f/w/f/w... you are feeding every time. You just don't believe it. Feeding recommendations are usually for almost twice what the plants really can use (that time), in soil. What nutrients the plant does not use, are captured temporarily by the soil to give to the plant on the next watering. When you come back with plain pH adjusted water, it reactivates those nutes temporarily stored in the soil, feeding the plant for a second time. Maybe your nutrients were meant to be used in a different method, such as hydro or coco, where you absolutely DO feed every time. In soil, the rules are different. And, if you bought hydro nutes, that could be part of the problem, since they are chelated to work at a different pH than you need to use in soil.

If you were using the nutrients native to the soil, instead of out of a bottle, then you do indeed use up the nutrients built into the soil. When you feed from a bottle with bioavailable nutrients, your plant uses those, instead of that which may be locked in the soil. What low ec are you talking about.. the ec of the soil? Don't worry about it... when you feed from a bottle your soil is essentially a root holder and nothing more.

Regarding the calmag every time... once you get to a baseline... sure, if it is needed. But don't think that your calmag is the solution to this problem... it is just one tool in the toolbox.

 

[Poezebeest]

It's not about not believing, it's about understanding. One does not learn anything when he does not understand the reasoning behind it
Like you said, recommendations are usually (lots) more of what the plant can use. That was my reasoning for giving smaller doses, every watering. I was giving little over half the recommendation, so when using your method I put less nutrients in the soil overall. Hence my confusion.

My nutrients are from the Plagron Terra line,I forgot to mention this in my initial post. So definitely not bio.

Due to the poor choice of my timetable, I'll keep it short. I have just enough time to water the plants before I go to work and read your post.

I have watered 3 of the 4 plants now with just water. The 4th plant, who was also the fasted deteriorating plant, had none. Pots where light, 4th was noticeable heavier.
Here is what on of those simple moist meter said (about 2/3ths into the pot), and I have watered accordingly. In steps, like your water recommendations.