Yellow & rust colored spots: can’t figure this out

[Cwmoore577]

I have two plants, one Zkittlez one GelatOG. Zkittlez is most effected.

Its week 6 and has pistils all over, likely in the middle or near the end of stretch.

It’s indoor in a 2x4 tent (8sqft)

Medium is coco in 3 gallon smart pots (Royal Gold Tupur - which is coco fiber, aged forest materials, perlite, basalt)

I’ve mostly watered them from a 15 gal reservoir with drip stakes handwatering every 3-4 days to make sure everything gets saturated.

My light is the 250 watt Series 2+ Red Spec LED from BudgetLED and it’s dimmed to about 80% until flower start. It’s right at 16-18” above the canopy.

My temps run steady at 75-77°F and my humidity runs a bit low at around high 40s/low 50s.

Ive used the microscope and no signs of any pests.



Watering schedule:

I water twice a day with the Lucas formula modified for coco (H3ad’s formula) although at a lower dosage, same ratio. Mixed into RO water. I water around 1/2 gallon each time (10-20% runoff).



0.5ml/gal Stout MSA (mono silicic acid)

1-2ml/gal CalMag (2% N, 3.5% Ca, 1% Mg, 0.1% Iron)

3ml/gal GH FloraMicro

4.5ml/gal GH FloraBloom



I ph to 5.8-6.0, mostly close to 5.8.

EC 0.6-0.8 and 500-600ppm.

Since I noticed the issues I’ve only been handwatering and not using the res and drippers.

 

[AdaminCO]

@Emilya is really good on deficiencies. Lets
see if she can help.

 

[Emilya Green]

Hi... I see several things ... the overall top yellowing I think is pointing to a lack of iron. The splotches randomly on the leaves are interesting and I am thinking a P deficiency is the cause of this, but it is yet unclear. I think that your pH is too high and you are having trouble picking up some of the elements that are most mobile at the lower end. With you coming in at 5.8 to 6.0, you might be drifting up out of the range a little too quickly in that medium, especially since you are letting it dry out between waterings. I would try coming in at a lower pH a few times to see if it changes the symptoms or makes them go away.... try 5.5 and see what happens. To take care of the larger yellowing problem though, I think you need to up your dosage a bit. Lucas method is cool, but you don't want to starve your plants either. I would also lose the calmag until you see clear need for the supplement. Too much Mg can cause troubles too if it builds up.

 

[Cwmoore577]

Hi... I see several things ... the overall top yellowing I think is pointing to a lack of iron. The splotches randomly on the leaves are interesting and I am thinking a P deficiency is the cause of this, but it is yet unclear. I think that your pH is too high and you are having trouble picking up some of the elements that are most mobile at the lower end. With you coming in at 5.8 to 6.0, you might be drifting up out of the range a little too quickly in that medium, especially since you are letting it dry out between waterings. I would try coming in at a lower pH a few times to see if it changes the symptoms or makes them go away.... try 5.5 and see what happens. To take care of the larger yellowing problem though, I think you need to up your dosage a bit. Lucas method is cool, but you don't want to starve your plants either. I would also lose the calmag until you see clear need for the supplement. Too much Mg can cause troubles too if it builds up.

Thanks Emily you’re always so helpful on here.
I’ll lower my ph for a bit and see if that helps at all.
Also I had been adding either the 1ml calmag or 0.5 grams Epsom salt as H3ad’s formula called for 1g Epsom each watering and I had a mg def early with this plant.
Here’s an old pic of it:

Should I still drop the calmag even with it having the iron in it? Micro is the only other thing with iron and the formula says to drop it after stretch which is soon.

Should I up the FloraBloom for more P? I was wondering about this anyway as my other (GelatOG) has a few purple petioles as well, otherwise healthy though.

 

[Emilya Green]

you are on your own as far as what Lucas says you must do... I have never been a fan. If your plant showed earlier it was a magnesium hog then it probably still needs some, but again, I would be very careful with it, especially applying epsom salt as that is a good way to get it to build up in your soil. I am not sure how much a gram is without weighing some out, but about 1 tbls per gallon is all I would ever want to load into soil for an entire grow. If Lucas says to pull back on the Iron, go ahead, but it is my belief that your top yellowing will just get worse if you do.

 

[Cwmoore577]

you are on your own as far as what Lucas says you must do... I have never been a fan. If your plant showed earlier it was a magnesium hog then it probably still needs some, but again, I would be very careful with it, especially applying epsom salt as that is a good way to get it to build up in your soil. I am not sure how much a gram is without weighing some out, but about 1 tbls per gallon is all I would ever want to load into soil for an entire grow. If Lucas says to pull back on the Iron, go ahead, but it is my belief that your top yellowing will just get worse if you do.

A half gram Epsom per gallon is close to a half tsp per 5 gallons so it’s not much at all. Sometimes I leave it out as well. I’ve never used Lucas before this either. Just decided to attempt it as I have the FloraSeries for the first time and was unsure how to exactly use them in a coco based medium.

Also unsure why this one plant is showing these spots/blotches and the other isn’t when they’re both watered from the same source. Difference in strain nutrient needs id assume?

 

[Emilya Green]

Also unsure why this one plant is showing these spots/blotches and the other isn’t when they’re both watered from the same source. Difference in strain nutrient needs id assume?

yes, and even in the same variety sometimes there are variations. Treat each plant in your room as a unique individual.

 

[Cwmoore577]

yes, and even in the same variety sometimes there are variations. Treat each plant in your room as a unique individual.

Ok will keep that in mind.
Do you think upping the FloraBloom, leaving the Epsom and calmag out for a bit and seeing how it responds is a good idea?

 

[Emilya Green]

Edit: I might up the FloraBloom, leave the Epsom out for a bit and see how it goes. Would you think that would be a good idea?

That is almost what I would do... but still wondering if bloom has the correct nutritional needs for a vegging plant... but when you find the right mix, yes, give more.

 

[Cwmoore577]

That is almost what I would do... but still wondering if bloom has the correct nutritional needs for a vegging plant... but when you find the right mix, yes, give more.

Well I’ll still have to use floramicro as Bloom doesn’t have any of the micronutrients in it. The original heads formula used 6ml Micro to 9ml bloom ratio for veg but during stretch had a week of 6ml Micro to 12ml bloom before dropping the Micro.

I guess I’ll try 3ml Micro and 6ml bloom and see how it does.

thank you Emily!

 

[Emilya Green]

oh... that comes from the formula? I don't want to second guess that for you then... dance with the one who brought you, don't change course in mid stream... and all those adages that tell you to keep on your course. Pay no attention to the grousing from the girl from Missouri.

 

[Cwmoore577]

oh... that comes from the formula? I don't want to second guess that for you then... dance with the one who brought you, don't change course in mid stream... and all those adages that tell you to keep on your course. Pay no attention to the grousing from the girl from Missouri.

Yea this is the basic gist.

 

[Cwmoore577]

Hey @Emilya
Didn’t know who else to ask.
It’s gotten much, much worse since it started flowering. Spotting now all over the plant and mostly on middle to top leaves. Bottoms leaves for the most part seem less affected.
I had been feeding the same 6/9 ratio at around 1.0ec up until a few days ago when I started to drop the nitrogen levels as it’s near mid flowering. I’m stumped. My other plant still unaffected and healthy.

 

[Emilya Green]

The key to understanding this is to know how the mobility of nutrients within the plant can affect the way a problem presents in the leaves. A nutrient mobile within the plant is able to be stored in the large fan leaves at the bottom of the plant and then moved when needed for the growth at the top. Non-mobile nutrients can not do this, so if there is something lacking that is non mobile, it has never been stored in the plant, so the top growth, the newest growth, is that which suffers the damage. Mobile nutrients when needed are moved first from the lower branches, and then it moves up the stalk slowly, taking what it needs from the leaves, to support the upper growth.

What we see here is that your damage is showing all over the plant, top, bottom and middle. There is one element that does this a lot in cannabis, because it is one of the few that is SEMI-Mobile in the plant. Magnesium deficiency can present all over the plant, all at the same time. This is what I see here... a very profound magnesium deficiency.

 

[Cwmoore577]

The key to understanding this is to know how the mobility of nutrients within the plant can affect the way a problem presents in the leaves. A nutrient mobile within the plant is able to be stored in the large fan leaves at the bottom of the plant and then moved when needed for the growth at the top. Non-mobile nutrients can not do this, so if there is something lacking that is non mobile, it has never been stored in the plant, so the top growth, the newest growth, is that which suffers the damage. Mobile nutrients when needed are moved first from the lower branches, and then it moves up the stalk slowly, taking what it needs from the leaves, to support the upper growth.

What we see here is that your damage is showing all over the plant, top, bottom and middle. There is one element that does this a lot in cannabis, because it is one of the few that is SEMI-Mobile in the plant. Magnesium deficiency can present all over the plant, all at the same time. This is what I see here... a very profound magnesium deficiency.

That’s the only thing I read that resembled what is happening but since I’ve been adding Epsom salt (1 gram per gallon or right over a tsp per 5 gallons) just about every watering I was hesitant to add any more. Everyone says Epsom salt can cause issues.
Should I increase it?

I also found that I have springtails all over in my runoff. Ugh.

 

[Emilya Green]

That’s the only thing I read that resembled what is happening but since I’ve been adding Epsom salt (1 gram per gallon or right over a tsp per 5 gallons) just about every watering I was hesitant to add any more. Everyone says Epsom salt can cause issues.
Should I increase it?

I also found that I have springtails all over in my runoff. Ugh.

NO, do not increase it. Try calmag+ instead.

 

[Cwmoore577]

NO, do not increase it. Try calmag+ instead.

Ok thankfully my last two waterings I used 5ml calmag+. Will try to save it.

Thanks as always Emily!

 

[Emilya Green]

keep in mind that mag damage is permanent. The supplements will stop it from progressing, but the damaged areas will never come back. If 70% of the leaf is gone, might as well remove it, but other than that, keep them on there so the plant can go back to them again if it needs to instead of taking out something new.

 

[Cwmoore577]

keep in mind that mag damage is permanent. The supplements will stop it from progressing, but the damaged areas will never come back. If 70% of the leaf is gone, might as well remove it, but other than that, keep them on there so the plant can go back to them again if it needs to instead of taking out something new.

Do you think it could be calcium excess causing the mg def? I read that could cause the wilting as well. There should be plenty mg in there for it to use but it’s getting worse pretty quickly.

 

[Emilya Green]

where would all your extra calcium be coming from?