Newbie with some specific Coco Coir/EC questions

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phxazcraig

phxazcraig

519
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I'm a first-time Coco Coir grower, using a 4x4 tent with a 600w HLG light and a DIY fertigation system as shown in cocoforcannabis.com. I grew two crops last year, the first being some autoflowers and the second 5 fabric pots of Ghost OG. Both these crops were in a soil mix I made. I did pretty much everything wrong with the autos and got 4 stunted plants off them for a total of 3 oz's. Basically I found the upper limits of too much light, too much water, too much nutes, etc. I did much better with photos, although I let them grow an extra month in the beginning as I underdid everything to avoid the mistakes of the first grow. The second crop started May 1st and was harvested Oct 10 with a dried yield of 18 ounces.

Now I'm trying fertigation and hydro for the first time, and figuring out what should be (and not be) in the water has me confused. So some specific questions:
1. What can/must I do with cal/mag? I cannot use my tap water as it comes out of the tap with a PPM of 400, which I'm led to believe is too high for young plants. (2 weeks at this time, started in Jiffy pots in red solo cups, and transplanted into Air Pots after a week.) I'm using RO or distilled water (I have both) which start out at about 20ppm.

When I mix in anywhere near the recommended amount of cal/mag, 2.5ml/gal, my PPM skyrockets out of range. This is basically my dilemma. I don't see how I can achieve a PPM goal by adding the 'right' amount of cal/mag. The first batch of water I put through the system was diluted about 5 to 1 after I mixed everything up. I figured better safe than sorry.

The second week of water I just went ahead and mixed things at the recommended dilution and left it at 500ppm or so - higher than desired. My question here is what sort of approach to take? Use cal/mag and let the PPM go where it goes (too high)? Mix all at the recommended ratios, then dilute with distilled water to hit a PPM goal? Or add cal/mag only up to desired PPM and stop, then mix nutes as directed?

2. I'm nearing the end of week three with the system, and I'm going to need to clean out the reservoir this weekend. I have concentrated peroxide, but no good instructions as to what to do here, Do I fill the reservoir, add some h2o2 and let it soak? Or just mix up a gallon and hit it with a scrub brush?

3. I have leftover Fox Farms nutes from the soil grow, though I did replace the Grow Big bottle with a hydroponics version of it. Do I use the other nutes (Big Bloom, later Tiger Bloom) or should I be looking for hydro versions of all three nutes?

4. Runoff - I'm unable to tell if I'm getting 10-20% runoff, because I haven't measured what's actually going into each pot through the halos. But I'm certainly able to check the PPM/EC and pH of the input and output water. I'm getting PPM rises of 50-200 points, depending on how much water I put through. I'd rather actually test the runoff to achieve some target than guess it's ok based on input/output volumes. Currently my halos drip water twice a day for 30 seconds each time, and I get about a gallon of runoff from all four plants. The DIY irrigation works very well, though you can't easily move things around once set up.

My four plants are looking very healthy at the moment. I just topped the most mature of the four plants at the 5th node. The other three should get to that point tomorrow. These plants looked bad in the solo cups, probably from overwatering. They were sickly and yellow, but since I've put them in the air pots and given a week of fertigation, they have greened up nicely and are growing well.

I don't think I've ever had healthier looking plants in terms of the leaf tips - no burnt tips (yet) or other discolorations. I feel like I must at least have things in the right ballpark for now. I'm using a Bluelabs pH controller set to 6.0 and adding ph Down in 1 second amounts every 10 minutes as needed. Air pump running full time. Basically the exact system described in the DIY instructions in the cocoforcannabis site. But all the stuff I have to mix? And the order I have to mix in? It's very complicated compared to my soil grows. I'm putting in Silicone (then 1 hour delay), cal/mag, fox farm nutes (just Grow Big and Big Bloom for now), then some humic acid and yucca wetting agent. I mix up 8-10 gallons and pour it into the (empty) reservoir 10 hours before next feeding and let the Bluelabs controller manage the pH.
 
DanC520

DanC520

517
143
I use same system in my 4x4. I just mix my nutes based off my base schedule and don’t pay attention to ppm, just ph. If they start to burn, I dial things back. I do go heavy on cal mag if under led.

I didn’t clean my res until run done. I just didn’t put organics in there and wasn’t too bad. That’s me though. My water not in there for more than a couple days.

not sure on nutes. I’ve just used gh whole time.

I get a lot of run off. I also feed a lot. Once in auto system I started with 3x a day, then 6x, then 9x. Just make sure you’re getting enough or salts will build.

idk if any of that helps, but my two cents for what it’s worth.
 
Anthem

Anthem

3,616
263
I'm a first-time Coco Coir grower, using a 4x4 tent with a 600w HLG light and a DIY fertigation system as shown in cocoforcannabis.com. I grew two crops last year, the first being some autoflowers and the second 5 fabric pots of Ghost OG. Both these crops were in a soil mix I made. I did pretty much everything wrong with the autos and got 4 stunted plants off them for a total of 3 oz's. Basically I found the upper limits of too much light, too much water, too much nutes, etc. I did much better with photos, although I let them grow an extra month in the beginning as I underdid everything to avoid the mistakes of the first grow. The second crop started May 1st and was harvested Oct 10 with a dried yield of 18 ounces.

Now I'm trying fertigation and hydro for the first time, and figuring out what should be (and not be) in the water has me confused. So some specific questions:
1. What can/must I do with cal/mag? I cannot use my tap water as it comes out of the tap with a PPM of 400, which I'm led to believe is too high for young plants. (2 weeks at this time, started in Jiffy pots in red solo cups, and transplanted into Air Pots after a week.) I'm using RO or distilled water (I have both) which start out at about 20ppm.

When I mix in anywhere near the recommended amount of cal/mag, 2.5ml/gal, my PPM skyrockets out of range. This is basically my dilemma. I don't see how I can achieve a PPM goal by adding the 'right' amount of cal/mag. The first batch of water I put through the system was diluted about 5 to 1 after I mixed everything up. I figured better safe than sorry.

The second week of water I just went ahead and mixed things at the recommended dilution and left it at 500ppm or so - higher than desired. My question here is what sort of approach to take? Use cal/mag and let the PPM go where it goes (too high)? Mix all at the recommended ratios, then dilute with distilled water to hit a PPM goal? Or add cal/mag only up to desired PPM and stop, then mix nutes as directed?

2. I'm nearing the end of week three with the system, and I'm going to need to clean out the reservoir this weekend. I have concentrated peroxide, but no good instructions as to what to do here, Do I fill the reservoir, add some h2o2 and let it soak? Or just mix up a gallon and hit it with a scrub brush?

3. I have leftover Fox Farms nutes from the soil grow, though I did replace the Grow Big bottle with a hydroponics version of it. Do I use the other nutes (Big Bloom, later Tiger Bloom) or should I be looking for hydro versions of all three nutes?

4. Runoff - I'm unable to tell if I'm getting 10-20% runoff, because I haven't measured what's actually going into each pot through the halos. But I'm certainly able to check the PPM/EC and pH of the input and output water. I'm getting PPM rises of 50-200 points, depending on how much water I put through. I'd rather actually test the runoff to achieve some target than guess it's ok based on input/output volumes. Currently my halos drip water twice a day for 30 seconds each time, and I get about a gallon of runoff from all four plants. The DIY irrigation works very well, though you can't easily move things around once set up.

My four plants are looking very healthy at the moment. I just topped the most mature of the four plants at the 5th node. The other three should get to that point tomorrow. These plants looked bad in the solo cups, probably from overwatering. They were sickly and yellow, but since I've put them in the air pots and given a week of fertigation, they have greened up nicely and are growing well.

I don't think I've ever had healthier looking plants in terms of the leaf tips - no burnt tips (yet) or other discolorations. I feel like I must at least have things in the right ballpark for now. I'm using a Bluelabs pH controller set to 6.0 and adding ph Down in 1 second amounts every 10 minutes as needed. Air pump running full time. Basically the exact system described in the DIY instructions in the cocoforcannabis site. But all the stuff I have to mix? And the order I have to mix in? It's very complicated compared to my soil grows. I'm putting in Silicone (then 1 hour delay), cal/mag, fox farm nutes (just Grow Big and Big Bloom for now), then some humic acid and yucca wetting agent. I mix up 8-10 gallons and pour it into the (empty) reservoir 10 hours before next feeding and let the Bluelabs controller manage the pH.
First off I do not do Coco any more. Because you basically are running a hydro system the way you are running. I do run hydro now. Cost and work load to go hydro made more sense so the coco and pots are gone. With that being said.
#1. You will need to add Cal Mag with the RO water. No way around it especial with Coco
#2. Nutrients I do not like the Fox Farms stuff. Never used it and there are numerous people coming to the site with issues using it.
#3. Your mix, Silca first is correct and let it set (what silca? Mono Silic Acid is ideal in Coco or Hydro. The stuff that comes out of Potash is not going to help unless you have bennis in the tank. Some do Cal Mag next and others do it last. IMO it does not make a difference. Just get the Silica in first.
#4. I run sterile with UC Roots so I only clean my rex between changes. I use a strong cleaning product and rinse and flush the rez before I start back up. Rex changes should be every week.
As the plants start to grow you will need to add waterings to keep the coco damp. I would suggest you figure out a way to run one of those halos for your 30 second run time and start figuring out your percentage of run off as this is important to help letch the excess salts out of the coco.
Lastly, there is a thread by Aquaman, watering Coco. Find it and read the whole thread. It will be the most helpful thing you can do for yourself. You can find it by looking at the search tool located at the top left of the page.
Good Luck
 
SofaKingHigh

SofaKingHigh

705
143
Ditch fox farm nutrients for coco, I have learned from experience and from many others having issues with it. I’m using Mega Crop and no looking back. It’s a 1 part dry nutrient and super easy to use with great results.
 
phxazcraig

phxazcraig

519
93
I now have 5 weeks of experience with this grow and can answer my own questions at least a bit now.

1. What can/must I do with cal/mag? I cannot use my tap water as it comes out of the tap with a PPM of 400, which I'm led to believe is too high for young plants. (2 weeks at this time, started in Jiffy pots in red solo cups, and transplanted into Air Pots after a week.) I'm using RO or distilled water (I have both) which start out at about 20ppm. When I mix in anywhere near the recommended amount of cal/mag, 2.5ml/gal, my PPM skyrockets out of range. This is basically my dilemma. I don't see how I can achieve a PPM goal by adding the 'right' amount of cal/mag. The first batch of water I put through the system was diluted about 5 to 1 after I mixed everything up. I figured better safe than sorry.
This was only an issue right at the start of vegetation when I was trying to keep total EC around 400-600, including nutes. By adding cal/mag (Calimagic) at 2.5ml/gal, I used up almost all of my EC right there. Once I got to the point of 800-1000EC, this wasn't really an issue. After about 3 weeks I switched away from Fox Farm into the GH trio - made the reservoir a lot cleaner if nothing else. The GH nute chart has my adding only 1.9ml/gal during flowering, so I'm able to relatively increase my nute strength. And I've also seen burnt leaf tips on all the plants.
The second week of water I just went ahead and mixed things at the recommended dilution and left it at 500ppm or so - higher than desired. My question here is what sort of approach to take? Use cal/mag and let the PPM go where it goes (too high)? Mix all at the recommended ratios, then dilute with distilled water to hit a PPM goal? Or add cal/mag only up to desired PPM and stop, then mix nutes as directed?

I start by mixing 11 gallons (and call it 10) per one of the GH charts. I then add RO water to dilute it, sometimes just to get the 14 gallon reservoir topped up. EC's typically end up in the 1100-1350 range. I'm increasing slightly during flowering, but I don't like seeing burnt leaf tips. Other than that, the plants look fantastic.
2. I'm nearing the end of week three with the system, and I'm going to need to clean out the reservoir this weekend. I have concentrated peroxide, but no good instructions as to what to do here, Do I fill the reservoir, add some h2o2 and let it soak? Or just mix up a gallon and hit it with a scrub brush?
A couple of times - especially because of Fox Farms Big Bloom. I think I've gone from organic to sterile. Consequently, and partly due to laziness, I've just been topping up the reservoir as needed instead of scrubbing out the whole thing. I've also been adding 2.5ml/gal of 33% h2o2 to the nutes to help control things like algae.

3. I have leftover Fox Farms nutes from the soil grow, though I did replace the Grow Big bottle with a hydroponics version of it. Do I use the other nutes (Big Bloom, later Tiger Bloom) or should I be looking for hydro versions of all three nutes?
Still don't know what I don't know here, but I've switched to GH partly just to simplify things as I was already doing all GH additives except nutes.
4. Runoff - I'm unable to tell if I'm getting 10-20% runoff, because I haven't measured what's actually going into each pot through the halos. But I'm certainly able to check the PPM/EC and pH of the input and output water. I'm getting PPM rises of 50-200 points, depending on how much water I put through. I'd rather actually test the runoff to achieve some target than guess it's ok based on input/output volumes. Currently my halos drip water twice a day for 30 seconds each time, and I get about a gallon of runoff from all four plants. The DIY irrigation works very well, though you can't easily move things around once set up.
I've learned a lot about this, though not the actual mechanism behind it. Partly it's a matter of enough runoff, partly timing. I found that at first my runoff EC was very low, as much as 800EC less than input. But as vegetation continued, the runoff EC began to rise a bit. However, at flowering initiation, it spiked. I think mostly due to the change in light cycle, but possibly also a matter of changed chemistry from flowering plants. In any case my runoff EC was up to 800 points HIGHER after 2 weeks of flowing, and I had to increase the amount of watering (runoff) each feeding. I went from 30 to 35 seconds, which is about 15% more water in than before. In 4 days my runoff EC dropped to about 100 points higher than input. I should note that one variable in this equation is starting with different nutes and strengths in the flowering stage. In any case I'm going to assume that it is normal and typical to see runoff EC build at start of flowering, and I suggest keeping a close eye on it at that stage.
I don't think I've ever had healthier looking plants in terms of the leaf tips - no burnt tips (yet) or other discolorations. I feel like I must at least have things in the right ballpark for now. I'm using a Bluelabs pH controller set to 6.0 and adding ph Down in 1 second amounts every 10 minutes as needed. Air pump running full time. Basically the exact system described in the DIY instructions in the cocoforcannabis site. But all the stuff I have to mix? And the order I have to mix in? It's very complicated compared to my soil grows. I'm putting in Silicone (then 1 hour delay), cal/mag, fox farm nutes (just Grow Big and Big Bloom for now), then some humic acid and yucca wetting agent. I mix up 8-10 gallons and pour it into the (empty) reservoir 10 hours before next feeding and let the Bluelabs controller manage the pH.
I've got a bit more information on silica over the past month, and some of it is directly contradicted by some people's beliefs here. I am using Silica Blast from Botainicaire. Here are two facts I can state:
1. pH: On the Silica Blast bottle, the last line of instructions states to set pH at 6.0.

2. Mixing order: Definitive articles (
I call them definitive if they come from the manufacturer of the product) all state to mix silica FIRST. At least one calls for a 10 minute delay after, another calls for a 60 minute delay. Botanicare doesn't mention any delay. See these links:

And here is one from Botanicare that seems pretty definitive on silica blast and cal/mag:

I'll quote them: "When using Silica Blast, always add Silica Blast into your reservoir FIRST followed by Cal-Mag. If Silica Blast is not being used and Cal-Mag is, Cal-Mag should be added FIRST, then add the remaining nutrients."
 
plumsmooth

plumsmooth

76
18
I use same system in my 4x4. I just mix my nutes based off my base schedule and don’t pay attention to ppm, just ph. If they start to burn, I dial things back. I do go heavy on cal mag if under led.

I didn’t clean my res until run done. I just didn’t put organics in there and wasn’t too bad. That’s me though. My water not in there for more than a couple days.

not sure on nutes. I’ve just used gh whole time.

I get a lot of run off. I also feed a lot. Once in auto system I started with 3x a day, then 6x, then 9x. Just make sure you’re getting enough or salts will build.

idk if any of that helps, but my two cents for what it’s worth.
Does the plant actually use more Calcium and Magnesium under LED or to the higher PPFD's just overall create more of a demand on Nutrients?
 
DanC520

DanC520

517
143
Does the plant actually use more Calcium and Magnesium under LED or to the higher PPFD's just overall create more of a demand on Nutrients?

Idk man. I’d be googling to try reply to this. All I know is need more in coco and even more under LEDs
 

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