Rust fungus or deficiency?

I've been giving general hydroponics nutrients and blue planet cal mag, so I dont see how this could be a deficiency, but I'm about 3.5 weeks from flower and over the last couple days most of my plants have been hit with these rust spots on the leaves, on both fan leaves and even small leaves close to the buds. What do you think it is and how do I go about fixing? Help fast please?!? Will it be better to harvest early since I'm so close (I dont want to, but dont want to lose my hard work either!)?

From what I'm seeing, maybe still is a calcium deficiency. Should I give calcium alone without magnesium? Or just extra maybe?

I'm leaning on cal/mag deficiency with the limited info provided.

What do the lower leaves look like? What medium are you growing in? You using tap or RO water and the order you're mixing nutes?

My Name is Mike said:

I'm leaning on cal/mag deficiency with the limited info provided.

What do the lower leaves look like? What medium are you growing in? You using tap or RO water and the order you're mixing nutes?

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My lights are off until 11, so I will take pictures of lower leaves then. I always do micro first, then grow (but just stopped grow this week since we are 3 weeks from harvest), then bloom, then cal mag. At first we had some major nutrient burn, so I found a different schedule which resolved that almost immediately. Now that we are further into flower, I think they might not be what they need, so I just this week switched to the drain to waste medium feeding schedule on the general hydroponics website. Below is the schedule we were following. We PH water in soil at about 6.4-6.5 and do not use RO water.

em091r said:

My lights are off until 11, so I will take pictures of lower leaves then. I always do micro first, then grow (but just stopped grow this week since we are 3 weeks from harvest), then bloom, then cal mag. At first we had some major nutrient burn, so I found a different schedule which resolved that almost immediately. Now that we are further into flower, I think they might not be what they need, so I just this week switched to the drain to waste medium feeding schedule on the general hydroponics website. Below is the schedule we were following. We PH water in soil at about 6.4-6.5 and do not use RO water.

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If you're using tap water, what's the ppm and ph of your water without any nutes added? Is it city or well water?

First potential issue is you should always add cal/mag first before any of the nutrients.

Make sure you add 1 nute at a time, mix well then start the next one. PH the water BEFORE you use it in soil. How are you PH the water in the soil?

"Rust fungus"...gave me a chuckle
Mix your Calmag first, then micro.

Ok, so I definitely did not know that about the cal mag, thanks so much for the tip! Its tap water from the city. Usually I have a PH around 9.5 right out of the tap (it fluctuates a bit on the day, but never less than 9). Due to it being so high, I always Ph down to about 6-6.5 then add nutes. Then once I've added, i ensure my PH is 6.3-6.5 prior to adding to my soil. And I do certainly mix one at a time. I will switch up my routine to do cal mag first. How much should I use to correct this issue? Maybe 5 mil per gallon until it's better? Also, I do not know what my PPM is. Due to you asking, I just ordered a meter on Amazon. hopefully I'll have in early next week and check. I'll post a pic of lower leaves below.

I would need to better zoom in on the areas but if it's fuzzy and on top of the leaf (not in it) then it's rust fungus. From the looks of it I would say 80% that it's RF.

Actually I am 100% it's RF now, I looked again and in the second to last pic you can see it's growing on the trichomes, thats not a deficiency. It's rust fungus 100%.

So I included some overall pictures, as my leaves seem a bit droopy today. On the small leaves it does appear fuzzy, although nothing comes off on my finger if I rub it. They seem to have gotten much worse just overnight and I added extra cal mag last night (5 ml per gallon)

Why did the other guy chuckle when I suggested it was rust fungus? I really don't want to treat the wrong problem. it is is rust fungus, would it be better to harvest early so my buds arent compromised? Will my bud suck if I do? I'm only 5 weeks into flower on monday, has average flower time of 55 days. (World of seeds Northern lights x big bud photoperiod, NOT the autoflower)

em091r said:

Ok, so I definitely did not know that about the cal mag, thanks so much for the tip! Its tap water from the city. Usually I have a PH around 9.5 right out of the tap (it fluctuates a bit on the day, but never less than 9). Due to it being so high, I always Ph down to about 6-6.5 then add nutes. Then once I've added, i ensure my PH is 6.3-6.5 prior to adding to my soil. And I do certainly mix one at a time. I will switch up my routine to do cal mag first. How much should I use to correct this issue? Maybe 5 mil per gallon until it's better? Also, I do not know what my PPM is. Due to you asking, I just ordered a meter on Amazon. hopefully I'll have in early next week and check. I'll post a pic of lower leaves below.

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The ppm is important to know to give you a rough estimate on how your baseline ppm water measures up. This is important so you know how much nutes to add or if you need to dial it down. You won't need much cal/mag since your tap will contain plenty. Only users that use RO or distilled water would generally want to use a cal/mag supplement since that water doesn't contain it.

Don't think of this as a deficiency, think of it as a lockout. Your plants were deficient in cal/mag not because you weren't giving enough, because your PH and nutes were not properly mixed thus locking out certain nutes from your plant being able to feed on. Resulting in a deficiency.

This is why.. do not PH your water before adding nutes. PH should be the LAST step in the process. Most nutes contain PH buffers. You'll want everything to settle and be well mixed, typically wait up to an hour after all has been mixed, then PH test and adjust before you feed plants.

1. PH and PPM test water out of the faucet.
2. Add half recommended dose of cal/mag, mix
3. Add Micro, mix
4. Add Bloom, mix
5. Allow to settle, test PH, adjust ph
6. Ready to use

Renfro said:

Actually I am 100% it's RF now, I looked again and in the second to last pic you can see it's growing on the trichomes, thats not a deficiency. It's rust fungus 100%.

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This may be in addition to him overcoming a nute lockout, but it's not just rust fungus. If you're 100% on RF that's on top of him needing to address why he experienced nute burn in the first place. Just want to make sure OP doesn't ignore one or other.

Si just to clarify, the way I've been doing things could have caused but burn and a deficiency at the same time? The note lockout thing you explained makes sense. This is my first grow, so I'm learning a lot, and definitely appreciate the advice!

em091r said:

Will my bud suck if I do?

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It would be terrible, smell like hay after dried. You have to let it finish out. Is your RH% too high, maybe at lights out?

You could perhaps use actinovate to help stop the RF. Other deficiencies are a minor problem compared to the RF as it could take over before they are ripe.

My humidity has been a bit on the high side since flower, my T6 fan runs constantly, but it ranges from 50-60%

em091r said:

. it is is rust fungus, would it be better to harvest early so my buds arent compromised? Will my bud suck if I do

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they are still too small, to be harvested that early wouldnt give a nice smoke... you need a magnifying glass, x120, then check to confirm... if its rust you may want to remove the worst hit leaves