Coco Soilless Water Retention & Buffering Issues

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skillet12

skillet12

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Hey yall,

Someone suggested to move this discussion to a new thread to keep it from cluttering the original. Here's some context:
Hey, coincidentally I've been using roots soilless for almost the same amount of time and with the same nutrient schedule (high fertigation) that you have. I'm a bit confused with this medium.

It seems like it holds a lot more water and compacts more than what I assume just coco and perlite would. I've noticed that after transplanting to larger containers, daily watering made everything droopy, slowed, and wrinkly until I started letting them dry for longer and eventually moved them into fabric pots.

The other confusing thing about it is that my runoff is always around 7.0-7.3 ph while the feed going in is 5.8-6.0 ph.

ppm of fert mix is around 630 and the source water is 1/2-3/4 of distilled water with the rest being tap water with a ph around 8.0 and ppm of 250-300

I'm running off the same schedule as op with GH flora trio, armor si, calimagic, diamond nectar, amino acids, and yucca. edit: forgot to mention I need to ph down with phosphoric acid bringing it from 6.5-7.5ph to 5.8-6.0ph

I'm waiting on a soil hydro-thermometer but air temperature stays at 73-76 F at night and at an rh of 55-60%. I've been concerned about soil temp but pots are slightly elevated in autopots (not on yet) with a rug separating the tent from the wood floor.

I'm worried more about the worm castings having bad air retention than coco. It seems like there's a lot of it but its hard to tell. I can go back to daily fertigating but they've been showing signs of over watering since transplant. It's hard to know what direction to go.

By treating it like soil, I just mean that I wasn't going to fertigate everyday until the plants fill the containers better. Eventually they'll be fed from the bottom when the roots are long enough to drink from the autopot basins so being underwatered won't be a problem by that point. They'll drink as much as they want

It gives the benefits of a soilless grow while still letting me spoon feed whats needed or dilute feed instantly.

Im in fabric pots so oxygen flows through all sides. When plants are fed from the bottom, the top medium drys and allows for constant airflow for breathing oxygen at the top of the roots. They are in gravity-filled basins so the root tips are always in water. It's similar to kratky but with a richer medium.

I forgot to mention that the ones in the larger containers have had a good bit of purple on the joints between stems and branches that seem to worsen after watering if they haven't dried enough. Could be phosphorus def but I need a pretty good dose of phosphoric acid to get the ph down so I doubt its that. The runt in the 1gal has never changed stem color but watering before it dries makes the new growth wrinkly and water logged. Purple may be genetic but its unstable so im doubting its the main reason.

Water temp has been pretty good so far but this week I've been extra aware to feed with cool/lukewarm water to mitigate shock. I'm honing in on all the little things to keep everything stable while I treat a bit of IV chlorosis. Its hard to tell if its root shock (2nd container was poorly chosen ending with transplant shock after moving to final fabric pot) ph or nutrient def/toxicity so I'm taking it slow and steady.

I'm still not sure what to think about the medium ph though. The medium always buffers to about 7.0 when testing runoff and medium ph. Its possible that the chlorosis is from a lack of iron, zinc or another mineral that needs a lower ph to be taken up. Did you mention that source water could somehow cause this even after ph-ing?

I tried buffering before even using the medium but regardless I assumed it would eventually acidify to my usual feed ph. I don't know what else it could be. The feed in the reservoir stays pretty stable after sitting for a couple days so I doubt its that. I understand that plants and microbes will buffer ph as they eat and create food for each other but I don't know exactly how that effects the ecosystem. The runt is going into a 5gal soon with a different coco perlite and peat mix so I can see if it behaves any differently. I wish I added peat at the beginning to hold a little acidity or just went straight coco and perlite.

A bit cluttered but this is where we're at. I'm mainly concerned about the medium ph and feed requirements at this point. I'm not able to fertigate daily per the schedule so I'm not sure they're fed enough. Feeding/watering will be easier once roots can reach the bottom and the autopots turn on.

Cheers!
 
Aqua Man

Aqua Man

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Hey yall,

Someone suggested to move this discussion to a new thread to keep it from cluttering the original. Here's some context:








A bit cluttered but this is where we're at. I'm mainly concerned about the medium ph and feed requirements at this point. I'm not able to fertigate daily per the schedule so I'm not sure they're fed enough. Feeding/watering will be easier once roots can reach the bottom and the autopots turn on.

Cheers!
Ok first can we get pics and a full history including media and testing, all nutrient and supplements, equipment and environmental parameters
 
skillet12

skillet12

19
3
Here's the main offender. Started in a rapid rooter before going to small plastic containers with Roots Soilless before moving to a larger plastic container and eventually the smartpot. This plant was by far the biggest and strongest until wind knocked it over right at the base of the stem. The second container seemed to have done a number on her as well. It held water and the roots were disturbed a good bit transplanting out. Sort of a perfect storm but the roots seem to be recovering and things have un-stalled for the most part. Hopefully I can steer it towards some good growth before flower.

It's on day 30 right now from germ. I've been using the attached schedule fertilizing every watering. I cross reference with GH's dtw schedule but I think I might need to move closer to that (basically double the micro, veg, and bloom than the high fert schedule) since I can't currently feed daily with how waterlogged the medium gets. I wish i used coco and perlite only.

Ferts/supplements on the schedule being used are Armor si, calimagic, flora trio, and diamond nectar. Additionally I add 10ml per gal of NftG Amino acid mix and NftG yucca extract. Current ppm in is around 630 with ec of 1.3 but was 600 and 1.2 last week. ph is 5.8-6.0. The supplements have all been in use together for a couple weeks. I started with just trio and calimagic but good response from the additional supps showed pretty quickly. Stems got really nice and thick.

Medium and runoff ph buffer to around 7.0ph no matter what.

Everything lives in a 2x4 tent with duct fan, humidity and temp control. A humidifier is placed in front of the passive intake. Air temps sits around 75-85 F lights on and 71-76 F lights out.

Lights was a 6400kCFL daylight bulb with two small white CFLs while I waited for new backordered LED, so it was taken into the sun for mornings. Current light is growcraft x3 installed just this week. Currently on low setting to get things acclimated but they love it so far.

To reiterate the past and current problems, everything seemed overwatered after potting up, keeping me from daily fertigation. Stems have shown a good bit of purple that i don't believe is genetic. Root stress from falling over exacerbated the purple and gave the whole plant a sad look with deficiencies until the roots and stem were re established. At some point during recovery, IV chlorosis started showing up. I eventually flushed 2 days ago (the roots soilless bag says to flush every 2 weeks..) ending with somewhat light fertigation before taking a step back to see where things go.

Pics show the current stage with IV chlorosis, thin leaves on new growth and some slightly contorted old leaves with light necrosis on the very bottom (I think they just never recovered from the fall and are a low priority for the plant to send resources but idk) It might be a bit better today but its hard to tell just yet. I want to FIM asap to match its sister but I don't know how healthy it needs to be before that.[Edit: The leaves are apparently blocking it in the pic but the most purple is on the stem between the 1st and 2nd nodes.]

Thanks for reading! Let me know if you have any ideas to share
 
Aqua Man

Aqua Man

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Here's the main offender. Started in a rapid rooter before going to small plastic containers with Roots Soilless before moving to a larger plastic container and eventually the smartpot. This plant was by far the biggest and strongest until wind knocked it over right at the base of the stem. The second container seemed to have done a number on her as well. It held water and the roots were disturbed a good bit transplanting out. Sort of a perfect storm but the roots seem to be recovering and things have un-stalled for the most part. Hopefully I can steer it towards some good growth before flower.

It's on day 30 right now from germ. I've been using the attached schedule fertilizing every watering. I cross reference with GH's dtw schedule but I think I might need to move closer to that (basically double the micro, veg, and bloom than the high fert schedule) since I can't currently feed daily with how waterlogged the medium gets. I wish i used coco and perlite only.

Ferts/supplements on the schedule being used are Armor si, calimagic, flora trio, and diamond nectar. Additionally I add 10ml per gal of NftG Amino acid mix and NftG yucca extract. Current ppm in is around 630 with ec of 1.3 but was 600 and 1.2 last week. ph is 5.8-6.0. The supplements have all been in use together for a couple weeks. I started with just trio and calimagic but good response from the additional supps showed pretty quickly. Stems got really nice and thick.

Medium and runoff ph buffer to around 7.0ph no matter what.

Everything lives in a 2x4 tent with duct fan, humidity and temp control. A humidifier is placed in front of the passive intake. Air temps sits around 75-85 F lights on and 71-76 F lights out.

Lights was a 6400kCFL daylight bulb with two small white CFLs while I waited for new backordered LED, so it was taken into the sun for mornings. Current light is growcraft x3 installed just this week. Currently on low setting to get things acclimated but they love it so far.

To reiterate the past and current problems, everything seemed overwatered after potting up, keeping me from daily fertigation. Stems have shown a good bit of purple that i don't believe is genetic. Root stress from falling over exacerbated the purple and gave the whole plant a sad look with deficiencies until the roots and stem were re established. At some point during recovery, IV chlorosis started showing up. I eventually flushed 2 days ago (the roots soilless bag says to flush every 2 weeks..) ending with somewhat light fertigation before taking a step back to see where things go.

Pics show the current stage with IV chlorosis, thin leaves on new growth and some slightly contorted old leaves with light necrosis on the very bottom (I think they just never recovered from the fall and are a low priority for the plant to send resources but idk) It might be a bit better today but its hard to tell just yet. I want to FIM asap to match its sister but I don't know how healthy it needs to be before that.[Edit: The leaves are apparently blocking it in the pic but the most purple is on the stem between the 1st and 2nd nodes.]

Thanks for reading! Let me know if you have any ideas to share
Thats a magnesium deficiency. Add 1g per gal of epsom salt (magnesium sulfate).

I see a bit of light stress so do you have a lux app to check the intensity?

Also what's your RH?
 
skillet12

skillet12

19
3
Thats a magnesium deficiency. Add 1g per gal of epsom salt (magnesium sulfate).

I see a bit of light stress so do you have a lux app to check the intensity?

Also what's your RH?

Cool, I'll order some. Do you think extra calimagic will help in the mean time or would the extra N and Cal be unhealthy. It looks like it could handle some extra N at least.

I have a lux meter but it's hard to trust the conversion to ppfd. I definitely gave them too much LED at first but I've moved it to 24' at 30-50% dim. The LED companies par tests say that height at max power is 940 ppfd. I should be around 400-600 ppfd with the dimming right now. I underestimated just how bright the light is so now I wanna make sure to give everything time to acclimate before I really up intensity. I know that theoretically these plants can continue to flourish at up to 2000 ppfd. I don't have the means for that obviously but I'm wondering how I balance all the variables as I bring up the light intensity.

I also totally forgot to mention the UVB light at the very top of the tent that comes on for 15min during mid day. I would do 10 minutes but my timer doesn't go that low. After a bit of time with the LED I'll have the UV turn on twice a day.

RH is usually 50-60% with the 68% being the highest its ever gotten and 45% the lowest. Leaf temp seems like it changes more than room temp so its hard to predict exactly what the ideal VPD without taking a few readings.
 
Aqua Man

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Cool, I'll order some. Do you think extra calimagic will help in the mean time or would the extra N and Cal be unhealthy. It looks like it could handle some extra N at least.

I have a lux meter but it's hard to trust the conversion to ppfd. I definitely gave them too much LED at first but I've moved it to 24' at 30-50% dim. The LED companies par tests say that height at max power is 940 ppfd. I should be around 400-600 ppfd with the dimming right now. I underestimated just how bright the light is so now I wanna make sure to give everything time to acclimate before I really up intensity. I know that theoretically these plants can continue to flourish at up to 2000 ppfd. I don't have the means for that obviously but I'm wondering how I balance all the variables as I bring up the light intensity.

I also totally forgot to mention the UVB light at the very top of the tent that comes on for 15min during mid day. I would do 10 minutes but my timer doesn't go that low. After a bit of time with the LED I'll have the UV turn on twice a day.

RH is usually 50-60% with the 68% being the highest its ever gotten and 45% the lowest. Leaf temp seems like it changes more than room temp so its hard to predict exactly what the ideal VPD without taking a few readings.
Don't convert it just gimmie the lux.

You can pick it up at the pharmacy or most grocery stores. Just make sure it's not scented or anything just pure epsom salt (mag sulfate)

Adding a bit of cal mag won't hurt but really best to just treat the mag deficiency
 
skillet12

skillet12

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Don't convert it just gimmie the lux.

You can pick it up at the pharmacy or most grocery stores. Just make sure it's not scented or anything just pure epsom salt (mag sulfate)

Adding a bit of cal mag won't hurt but really best to just treat the mag deficiency
The lux is currently 12200 right now
 
skillet12

skillet12

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Hmm seems low. You sure that's not just maxing out your meter?

No, the meter goes to 99900lux. The light was on too high this morning so I'm just keeping it that low so they don't get too much for the day. I'm being a little overly cautious to be safe while things are acclimating and recovering. At max power 24" up the max is about 58000lux

This LED is a beast especially compared to the cfl's from before. I'm gonna bring the intensity up a bit everyday. I'm not quite sure how much per day but I think the goal I'm going for is around 700 ppfd for the rest of the 18/6 cycle.
 
Aqua Man

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No, the meter goes to 99900lux. The light was on too high this morning so I'm just keeping it that low so they don't get too much for the day. I'm being a little overly cautious to be safe while things are acclimating and recovering. At max power 24" up the max is about 58000lux

This LED is a beast especially compared to the cfl's from before. I'm gonna bring the intensity up a bit everyday. I'm not quite sure how much per day but I think the goal I'm going for is around 700 ppfd for the rest of the 18/6 cycle.
At that stage of growth 20-25k lux
 
skillet12

skillet12

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Maybe 30k
Cool, I'll change it to 20k tomorrow and see how far I can ramp it up through the week. Things are looking a bit better already so lets see where we can take this. Thanks for all the diagnosis and all the words of wisdom! I'll update in a week or so to let you know how things went
 
Aqua Man

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Cool, I'll change it to 20k tomorrow and see how far I can ramp it up through the week. Things are looking a bit better already so lets see where we can take this. Thanks for all the diagnosis and all the words of wisdom! I'll update in a week or so to let you know how things went
Good luck... Ah screw luck you got this bro.
 
skillet12

skillet12

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Yo yo, just a quick update. Will post update pics soon.

Plant is looking much bigger and healthier. The gravity fed bottom feed system has pretty much solved the water retention problem though the medium is still a bit spongy. Next time its all coco and perlite. Finally got topping done and trellising up, though later than I'd hoped. Probably gonna need extra veg time to get all the branches to canopy height.

Anyways, some leaves on both plants are still showing slight chlorosis. I'm pretty sure that the main cause is ph. Everything is getting at least the necessary amount of magnesium and other fertilizers but my reservoir always seems to want to buffer toward 7.0 ph. I'm really at a loss for what to do about it. After filling, I generally only need a small dose of phosphoric acid to get the ph below 6.0 but as time goes on the ph rises slowly and more ph down is needed. The chlorosis could even be an excess of phosphoric acid but there aren't any other signs beyond an apparent light magnesium or micronutrient deficiency. I recently switched to RO water but the issue has remained the same.

What could be causing this ph problem? Could humic or fulvic acid be buffering the solution or are there other factors that could be at play? I'd hate to have to empty and fill the reservoir every two days to keep a ph close to 6.0ph. I'm thinking of even adding sulfuric acid as a ph down replacement to keep an away from an excess of P if I need to fix it daily
 
Aqua Man

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Yo yo, just a quick update. Will post update pics soon.

Plant is looking much bigger and healthier. The gravity fed bottom feed system has pretty much solved the water retention problem though the medium is still a bit spongy. Next time its all coco and perlite. Finally got topping done and trellising up, though later than I'd hoped. Probably gonna need extra veg time to get all the branches to canopy height.

Anyways, some leaves on both plants are still showing slight chlorosis. I'm pretty sure that the main cause is ph. Everything is getting at least the necessary amount of magnesium and other fertilizers but my reservoir always seems to want to buffer toward 7.0 ph. I'm really at a loss for what to do about it. After filling, I generally only need a small dose of phosphoric acid to get the ph below 6.0 but as time goes on the ph rises slowly and more ph down is needed. The chlorosis could even be an excess of phosphoric acid but there aren't any other signs beyond an apparent light magnesium or micronutrient deficiency. I recently switched to RO water but the issue has remained the same.

What could be causing this ph problem? Could humic or fulvic acid be buffering the solution or are there other factors that could be at play? I'd hate to have to empty and fill the reservoir every two days to keep a ph close to 6.0ph. I'm thinking of even adding sulfuric acid as a ph down replacement to keep an away from an excess of P if I need to fix it daily
could be partly water source. to much lime. High amount of carbonate and bicarbonate sources... hard to say
 
skillet12

skillet12

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could be partly water source. to much lime. High amount of carbonate and bicarbonate sources... hard to say

Yeah I was thinking the same. I just switched out the res with 100% RO source water and I haven't even had to adjust ph on the new mix. I guess that 20% or so of tap was alkaline enough to make a steady 6.0ph pretty much impossible. The well water leaves limescale on everything and goes through a water softener so I'm just gonna take all that out of the equation.

I actually learned the details about how alkalinity in source water affects ph from a post you made on a different thread, so thanks!
 
Aqua Man

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Yeah I was thinking the same. I just switched out the res with 100% RO source water and I haven't even had to adjust ph on the new mix. I guess that 20% or so of tap was alkaline enough to make a steady 6.0ph pretty much impossible. The well water leaves limescale on everything and goes through a water softener so I'm just gonna take all that out of the equation.

I actually learned the details about how alkalinity in source water affects ph from a post you made on a different thread, so thanks!
Sorry been away a couple days. Is this hydro? What nutrients and additives are you using?
 
skillet12

skillet12

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Yeah, its soilless with mostly coco and perlite. The fertilizer i'm using is GH flora trio with GH silica, GH calmag, GH humic acid, RAW amino acids, RAW yucca, and SLF-100 enzymes in every batch. Lately i've been adding a bit of epsom salt or a little raw vitamin b for a little extra magnesium. Now that I'm using all RO I might just add more calmag instead.

On a different note, do you know anything about how microbial life effects a soilless system? I'm having trouble finding info on it. Obviously, the microbes don't eat mineral nutrients but are the sugars fed to them by the roots of the plant enough to support a thriving ecosystem? Would they aid the plant even if there's no organic matter to break down? I'm using a bottom fed system so there's no way they could be flushed out
 
Aqua Man

Aqua Man

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Yeah, its soilless with mostly coco and perlite. The fertilizer i'm using is GH flora trio with GH silica, GH calmag, GH humic acid, RAW amino acids, RAW yucca, and SLF-100 enzymes in every batch. Lately i've been adding a bit of epsom salt or a little raw vitamin b for a little extra magnesium. Now that I'm using all RO I might just add more calmag instead.

On a different note, do you know anything about how microbial life effects a soilless system? I'm having trouble finding info on it. Obviously, the microbes don't eat mineral nutrients but are the sugars fed to them by the roots of the plant enough to support a thriving ecosystem? Would they aid the plant even if there's no organic matter to break down? I'm using a bottom fed system so there's no way they could be flushed out
Coco is a great media for microbial life. Sure the roots will feed them and yes some of the salt ferts benefit from them. Bacteria produce enzymes they are not really living and it's these enzymes that will convert nutrient forms. It's a really complex topic.

But yes they absolutely aid the plants and there is still organic matter as the roots shed and some may die. Beneficial bacteria with salt or organic nutrients are absolutely important.
 
skillet12

skillet12

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Cool! It seems like a really interesting topic that I haven't been able to find much indepth information on.

My microbial life seems to be flourishing if the fungi reaching around the lower edges of the smartpot are any indication. I'm wondering how this effects the ideal feed ph. Do the microbes need a slightly higher ph above 6.0 to thrive and if so, do they allow a wider ph range in the rhizosphere to compensate for minerals taken up below 6.0?
 
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