Newer leaves yellowing, nutrient issues?

[coo_kie]

Hi everyone,
here we go again.

I'm into this little problem and I wanna solve it before it gets too big.
Plants are almost 5 week into flowering.
Lights: Lumatek Attis 300W Pro
Temperatures: 23°C (lights on)/ 19°C (lights off).
RH: about 55%
Soil: Biobizz Light Mix
Fan: yes
Other air circulation/filters: none
Last two waterings:

1. plain water, PH 6.3, EC 2.2
2. water + (0,1 ml/L CalMag), PH 6.5, EC 1.0 (last one)

Last runoff values: PH 6.5, EC 2.2
(All values of one plant, but the result is close in the others aswell)

Everything so far was fine until two days ago, when I started seeing some general yellowing more on the newer leaves rather than the older ones at the bottom. Still, there's some minor yellowing that happens more at the bottom on the other plants aswell.
I do not follow any particular feeding schedule, since it seems to me that they didn’t demand that much of nutrients at all. They’ve been fed plain water 95% of the time.
You can notice there is some yellowing on the tips. Maybe it’s the hard water, so I’m trying to lower EC. Counting this, it happened twice. The first time I solved this flushing at low EC.
I ran into nutrient lockout growing outdoors so I’m trying not do it again :’)
At the end, what do you say, guys? I can’t think of something else but nutrient def.
Do you agree or should I look into something else?
If it helps, yellowing's spreading quite fast.

Thanks in advance for helping.

 

[Three Berries]

Needs more N IMHO.

 

[led05]

Major Fe & slight Mg deficiency, maybe a tad more N could help but then you need more others too, to kept up…

A Species of plant doesn’t matter much, they all talk the same… this is a great chart for people of all level experience, cannabis & peppers are very similar, more so than tomatoes imo and I grow tons of all 3 species

You do a foliar spray with chelated micros Fe dominate your plants look all Perty again quickly

 

[Corpselover Fat]

Your starving the plant! Biobizz light mix is indeed very light on nutes. Good for seedlings, but needs quite a bit of nutes to grow and flower.

 

[Corpselover Fat]

I looked again and your water is 1ec with only a bit of calmag? What is it out the tap? You definitely don't need calmag, but it's probably what kept your plant alive as it's basically a nitrate nutrient.

 

[coo_kie]

I thought they might starve but 'till now leaves were dark green and I "read" it as "enough N", but I might be wrong and it could just be plants genetics. I'm gonna water with 2ml/L BioGrow, 1.5ml/L BioBloom, adding 1ml/L of TopMax.
I know calmag it's generally more effective with soft water. I don't get that soft water at all, indeed I have to mix multiple water sources to get to that sweet point (it's either too low or too high).
I don't have decent shops nearby, but I'll try to feed with chelated iron if I manage to find it. Meanwhile, I'm gonna help them gradually introducing nutes and wait for reaction in the next couple of days.
I'll keep you posted

 

[Corpselover Fat]

^ biobizz nutes are a little slow acting. Think about adding a bit of soil on top to release a bit of nutes for the plant.

And I meant that if your water is close to 1ec out the tap you have more than enough cal and mag in your water. The water may be problematic for growing.

 

[coo_kie]

^ biobizz nutes are a little slow acting. Think about adding a bit of soil on top to release a bit of nutes for the plant.

And I meant that if your water is close to 1ec out the tap you have more than enough cal and mag in your water. The water may be problematic for growing.

At the end I fed them a little less than what I said. I'm planning on feeding smaller amounts in multiple waterings rather than going in one shot.
I agree that CalMag wasn't probably needed, given the EC.
You state the water can be an issue, are you referring to its hardness or something else? My tap water is actually 4.5 EC and I lower that by using rain water at 0.2 EC. Also, I added a bit of soil (it was BioBizz All Mix, nothing else left) about 10 days ago when I noticed some of it was lost from the bottom between waterings.

For the record, watered with 7,5L:
- PH: 6.5
- EC: 1.3
- Biogrow: 1.5ml/L
- Biobloom: 1ml/L
- Topmax: 0.7ml/L

I'm posting more pictures from 30 minutes ago below, even though nothing's really changed.

 

[led05]

Clear Fe deficiency; GL - peace

 

[troutman]

I like greensand for iron. But don't mind using rusty nails either.

 

[Creeperpark]

If a pH creeps up above 7, iron will slowly become locked out. Using tap water that is high in alkalinity over time will raise the hydroxyl content in the container causing this. Your leaves are showing chlorosis.

High pH​

When the substrate pH is elevated, cannabis can develop interveinal chlorosis (yellowing) on the younger leaves. This is a common situation that occurs with many greenhouse-grown species, such as petunias, when the increased substrate pH makes micronutrients such as Fe unavailable to the plant. This symptomology or lockout can occur even if adequate Fe levels are being provided in the fertilizer. While deficiencies of other micronutrients such as B, Cu, Mn and Zn also can occur, problems of Fe lockout are most commonly observed.

Do a pour-though with distilled water and get a pH reading from the run-off. If the pH is high then reduce the amount of tap water with pure water to lower the pH.

 

[Creeperpark]

Always test when you are having any kind of problems with your plants.

Here's how I do a pour-through for a positive reading when I'm having even small problems.

Wait until the "watering day" and water your plants with the water you use and water to saturation. Water until you start to just start to get run off and stop, "heavy container" = water to saturation.

Wait 30 minutes, you can celebrate your pH meter while you wait.

After 30 minutes, add a small amount of deionized or distilled water to the plant container, until it starts to come out the bottom, just enough to collect a sample, you only need 50 to 100 mL of leachate. Make sure the water tray is super clean before you get a sample. Take the pure sample and test the EC, TDS, or ppm and the pH.

If you know your EC & pH you know what you are doing. If you don't then you don't know what you are doing.

 

[coo_kie]

So:
I'm still at the starting point I guess and maybe I'm wrong with readings, maybe I'm wrong with nutes (giving too little that I can't see any improvements or breaking "things" that once worked), maybe I'm giving them what they do not need.
I'm not sure about anything, yet yellowing is still there. I'm kind of annoyed from this situation and I suck when it comes to identifying these problems. I read Biobizz labels in order to see whether they contained enough iron to help them out and at the end I didn't come to a conclusion.

The major problem here it's definitely me, but I want to hear from you guys if EC really matter in these scenarios. I have this feeling I'm missing something important and I don't know what.

By the way, I watered with 9,5L and:
- 2ml/L BioGrow
- 1.5ml/L BioBloom
- 1ml/L TopMax
- 0.1ml/L Calmag
- PH: 6.6
- EC: 1.5

Should I increase?
One note: the last watering I said it was 1.3EC and that wasn't correct. Maybe around 2 to 2.5 is much more realistic since 1.3 was the reading (forgive me) before adding nutes.

Runoff (not after 30 minutes, but after 10), with cleaned tray after after pouring 0.07EC water (not PH):
- PH: 6.7
- EC: 4.8

Always test when you are having any kind of problems with your plants.

Here's how I do a pour-through for a positive reading when I'm having even small problems.

Wait until the "watering day" and water your plants with the water you use and water to saturation. Water until you start to just start to get run off and stop, "heavy container" = water to saturation.

Wait 30 minutes, you can celebrate your pH meter while you wait.

After 30 minutes, add a small amount of deionized or distilled water to the plant container, until it starts to come out the bottom, just enough to collect a sample, you only need 50 to 100 mL of leachate. Make sure the water tray is super clean before you get a sample. Take the pure sample and test the EC, TDS, or ppm and the pH.

If you know your EC & pH you know what you are doing. If you don't then you don't know what you are doing.

I read several articles about measuring runoff and none of them mentioned this 30 minutes waiting. I'm curious to know how much a reading can change. Have you got any experience/comparison?
If I have to wait 30 minutes, I'm gonna celebrate my plants rather than the pH meter, maybe with a chair.

Anyway, I know one thing for sure: pH is ok, so I can safely put that out of the equation.

It might not be a solution, but maybe I'll try a new medium next time just to have another experience. This BioBizz light mix got a little bit too compact and I don't like it as it can lead to other problems. Even if I don't change it, I'm gonna add some expanded clay pebbles.

I once had somehow a beginning of iron deficiency with very light green colors right in the middle of the plant (you got what I'm saying), but I wouldn't have said that this one looked similar.

Some photos today:

Thanks for your patience guys.

 

[Creeperpark]

Waiting 30 minutes after hydrating to test has a good reason however 10 will work. Good job.
After you got your reading I see that the EC is too high and causing problems.

I'm not sure what you mean with the line below.
0.1ml/L Calmag is not a mL? Are you using 1ml/L Calmag or 0.1ml/L

Your EC is too high of an EC for peat. I keep my peat in the container about 750 to 1200 ppm or 1.5 to 2.0 EC max.

Be gentle at this point because you and save those plants easily. You can lower the EC by just using cal-mag water for a while and that's all. The EC will slowly drop after a few waterings. The EC you have will be plenty all the way down to 2.0 EC so put your fertilizer away until then.

I never flush because the over-saturation of the soil will cut all the oxygen the roots "need in flowering". The plants need more dry time than wet time so be careful with watering. After the EC drops they should respond.

 

[Three Berries]

What I do is when wanting to measure runoff pH is water to runoff, then pour the run off back in and wait 30 minutes to measure that run off. This eliminates any pH changes from dried nutes in the pan and gives a more homogeneous reading from the medium, or so I figgure.

 

[led05]

dude, just spray your plants foliar with Fe already, it's that simple... the bane of cannabis growers, immense over complication

 

[coo_kie]

Waiting 30 minutes after hydrating to test has a good reason however 10 will work. Good job.
After you got your reading I see that the EC is too high and causing problems.

I'm not sure what you mean with the line below.
0.1ml/L Calmag is not a mL? Are you using 1ml/L Calmag or 0.1ml/L

Your EC is too high of an EC for peat. I keep my peat in the container about 750 to 1200 ppm or 1.5 to 2.0 EC max.

Be gentle at this point because you and save those plants easily. You can lower the EC by just using cal-mag water for a while and that's all. The EC will slowly drop after a few waterings. The EC you have will be plenty all the way down to 2.0 EC so put your fertilizer away until then.

I never flush because the over-saturation of the soil will cut all the oxygen the roots "need in flowering". The plants need more dry time than wet time so be careful with watering. After the EC drops they should respond.

I confirm I used 0.1ml/L and not 1ml/L. It was just to enrich a little bit the water since it didn't come from tap.
I agree with what you said. First and foremost I think I should lower EC by doing exactly what I did in the first place and then adjust nutes accordingly. I'll try not to flush them but I think it might be helpful if I do it once and then water regularly.

dude, just spray your plants foliar with Fe already, it's that simple... the bane of cannabis growers, immense over complication

As far as this, I ordered 20gr chelated iron powder on amazon. I'll spray it on monday evening as soon as lights turn off. You're right, gotta find the right balance between over simplification and over complication.
I'll keep you posted guys.

What I do is when wanting to measure runoff pH is water to runoff, then pour the run off back in and wait 30 minutes to measure that run off. This eliminates any pH changes from dried nutes in the pan and gives a more homogeneous reading from the medium, or so I figgure.

I get it, and I'll try doing both measurements (right after watering and 30 minutes after) to see the difference.

 

[Armate Otro]

My tap water is actually 4.5 EC

damn! thats hard as a rock

 

[coo_kie]

damn! thats hard as a rock

It's water from the well. Haven't done any research yet, so I don't know if it should be that hard

 

[Creeperpark]

damn! thats hard as a rock

It's water from the well. Haven't done any research yet, so I don't know if it should be that hard

That's your whole problem Hard 'tap" water. Thanks for info a little late. Know wonder your plants are turning yellow with added nutrients. You can spray iron on your plants all you want and waste your money but its not going to fix the problem. Everything goes j-waky towards the end when you use hard tap water. The pH will always swing super high after you water when using hard tap water. It can be hours later but that's why your plants are turning yellow. Because the accumulated hydroxy from all the past waterings has made the soil alkaline locking out iron. As long as you use that water it will still do what its doing. Acid only works temporarily for a little while and then swings back up because of the high accumulation.