Older leaves turning rusty/gold.

I cannot get pictures right now b/c I cannot find my camera charger. Just yesterday I upped my nutrients (CNS17 grow) up to 20ml/1gal. 3 to 4 hours after feeding I noticed the some leaves with a problem. They look as if somebody to a gold sharpie and marked on them.

I thought it was nute burn going from 1/2 strength to full but it also looks like either calcium or boron deficiency. I cannot figure it out. What steps can I take to pinpoint the issue?

I am using Nutrifield Coco Coir (100%). I also have 5ml CalMag+ mixed into my feed water already.

The pics are bad (phone) but those spots are gold to the look and under light they give off a shine. This is on about 4 or 5 of them.

That leaf twisting makes me believe you have some ph issues. In coco u should be ph'ing all your water between 5.6 and 6.2 being consistant as you can.

Also what ppm or nute strength are you feeding at?

What temps and humidity are they experiencing? What's your light source? And is there a fan blowing directly on them? Kinda looks like windburn I get on seedlings when a fans blowign on them too long. The glossiness shoots down the windburn tho, cuz it means ur rh is most likely above 40%.

I have been using ph drops and shooting for 6.0 range. PPM for the nutes was at 890. Temps are now at a steady 82degrees with 36-40% Humidity. Three 26w daylight cfl's and one 23w soft white cfl. I do have a fan blowing on them that I need to replace. The lowest speed is awfully fast.


The problem started after I raised my cns17 grow to full (20ml /1gallon). The ph was measuring low but then after the nutes sat(in my jar) the ph fluctuated. Also ppm at that time was jumping between 900 and 1100.

Krants said:

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The pics are bad (phone) but those spots are gold to the look and under light they give off a shine. This is on about 4 or 5 of them.

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I have been growing in Coco for about 4 years now. And use the same exact nutrients for grow as you have. well at least until it is gone. Never allow your PH to go above 6.0. NEVER.
The nutrients should not be your problem. How much run off are you allowing for. For instance, if you feed each plant one gallon, how much comes out the bottom. So please give how much water you give each plant, how often, and how much comes out the bottom. Also how large are the pots or grow bags you are useing. i use two gallon grow bags and give them a gallon every 3 days or so. A picture of the whole plant and how old it is would be helpful as well. Also, how many coco crops do you have under your belt?

I would be willing to bet you are right on the money with ph issue AND windburn. I never knew of windburn and pictures of it do look very similar to parts of the plant.

Krants said:

I have been using ph drops and shooting for 6.0 range. PPM for the nutes was at 890. Temps are now at a steady 82degrees with 36-40% Humidity. Three 26w daylight cfl's and one 23w soft white cfl. I do have a fan blowing on them that I need to replace. The lowest speed is awfully fast.


The problem started after I raised my cns17 grow to full (20ml /1gallon). The ph was measuring low but then after the nutes sat(in my jar) the ph fluctuated. Also ppm at that time was jumping between 900 and 1100.

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I would be shooting for no higher then 5.8 PH. Once you give me the other info needed I am pretty sure i can get you dialed in. OH!!!! What strain are you growing?

Well this is my first coco crop (first crop ever actually). Imix my nutrients in a 1gallon jar and feed from said jar. I do not measure the amount of water they get but do allow for a good runoff. The pot this plant is in is a 6" pot. The plant is 20 days old from seed. This was the plant about 3-4 days ago. The strain is a Tangerine Dream bagseed. Almost forgot, I water usually once a day every morning. Not soaked but moist conditions.

Hmm, Well you can not Soak Coco. But also if you have enough run off, how can you water light enough to do as you state? You have not given me one answer to any of my questions. You say you mix up a gallon of nutrients. Well, you could have 10 plants splitting that one gallon. I can already picturer your problem. But until I get the answers I need to make it more then a guess, I am not stateing it. You state you have enough run off. Hmmm. I wonder how you know this if this is your first crop. Not trying to be a jerk wad here. But giving your oppinion here, as an answer, is not helping.

Well to clear things up I am only running this single plant. I do understand where you are coming from with the "enough runoff" comment. I am sorry. I will start measuring out how much I give it per watering. I can not say at this time for certain how much runoff it is getting but the tray i am using is an 8inch round dinner bowl about 2inches deep. The runoff fills this up about 1/4 of the bowl.

Now that I've seen the whole plant I'm pretty sure its ph and windburn, little plants can be sensitive to the wind.

I've had ph up to 6.4 with good results in coco, now I aim for 5.9 to 6.

Some ppl I know only feed at 6.2-6.3. The method is, as coco dries, water evaporates, leaving a stronger nute concentration in the coco, which in turn causes a drop in the cocos ph, so by feeding at 6.3, as the ph drops to 5.7 or so, you have hit every ph allowing for every nutrients maximum availability.

Overall she looks fine, you probably feeding on the high end of things, but then again I'm a light feeder.

I water daily, and feed bi daily. With about 20% runoff every watering which is fundamental. With 20% runoff every watering and a feed water feed water schedule, I never have to do a "conventional flush" the entire cycle.

That's how I measure my runoff too, I've never really "measured" it, that's not of super inportance. I always try and fill my tray at least 1/4, but I always use all the nutes I mix so more like 1/2 of the tray.

So, TheLastWood, do you think I should do anything besides a different fan and fixing the ph?

Took the fan out put in a smaller fan. Not blowing around as bad by far. Also, I measured the amount I water with. 1 cup with 15-20% runoff.

Ph is important, its a logorithmic scale, each point is 10x more acidic than the point above it. For example, a ph of 6.0 is 10x more acidic than a ph of 7.0 and a ph 5.0 is 100x more acidic than ph 7.0

I would HIGHLY suggest you buy an electronic ph meter.mine was only 40$ and I calibrate it 1x a week..

Coco is simple, once you get your feeding schedule down, all you have to do is ph everything to 6.0 and u should never have a problem.

As I said ur feeding on the high side of things.

TheLastWood said:

Some ppl I know only feed at 6.2-6.3. The method is, as coco dries, water evaporates, leaving a stronger nute concentration in the coco, which in turn causes a drop in the cocos ph, so by feeding at 6.3, as the ph drops to 5.7 or so, you have hit every ph allowing for every nutrients maximum availability.

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What you are saying is only partially true. Your PH will either Spike or Drop depending on which nutrients you use. If you use Canna Nutrients you will see your PH spike instead of droping.

He says that he has a 8" bowl that is 2" deep and the run off fills it 1/4 full. That is not much run off from my calculations. I bet he has a big salt build up which is either spikeing or bottoming out his PH. He should be getting about 1/4-1/3 gallon of run off. What he should do is PH to 5.8 give it a good heavy watering allowing about 1/2 gallon of run off. take this run off and mix it. then take a sample of it from half way in depth. Then check this for PH.

I have my plants in a 14"X16" tub and it fills to about 2.5 inches worth of run off. I check the PH of my Coco about once a week, just to make sure it isn't going all freaky with salts.

One thing though. Did you add anything to your coco like Manure or something?

No it is 100% coco. I am using the Nutrifield brand. So in my 6" pot you are saying I should be having 4 cups worth of runoff normally? Also when doing this ph'ed flush, can you elaborate on mixing the runoff, I am confused at the moment. Do you mean allow for 1/2 gallon runoff and then mix this runoff with some of the coco itself and then test that for ph?

Krants said:

No it is 100% coco. I am using the Nutrifield brand. So in my 6" pot you are saying I should be having 4 cups worth of runoff normally? Also when doing this ph'ed flush, can you elaborate on mixing the runoff, I am confused at the moment. Do you mean allow for 1/2 gallon runoff and then mix this runoff with some of the coco itself and then test that for ph?

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No, just stir it up and then take a small sample from the middle of it. But not from the top and not from the bottom. This will give you a pretty representative sample. then check the PH of it. This will give you a good idea of what is going on inside your coco.

Ok I have gotten most everything fixed. Re-mixed my feed and ph'ed appropriately at 5.8. Also, roots were coming out the drainage of the 6" pot and circling UNDER my pot so I transplanted to a 2g smart pot. Everything is going better now.
Thank you Lord Dangly Bits and TheLastWood.