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Noob with possible pH issues, soil

Hi All. This is my first grow, and I've been experiencing some issues the past 3-4 weeks. I'd be very grateful for any constructive input. If I'm missing anything please let me know and I will try to quickly provide the info. I'd also be happy to provide more pics if needed.

Grow medium: Soil ( made myself - 40% compost, 30% sphagnum peat moss, 30% perlite ). Mixed by hand. Mistake 1.
Container: 20 gallon fabric pots. I realize this is too big of a container now.. Mistake 2.
Grow area: 8x20' greenhouse. 8' ceiling.
Water: 80% RO, 20% well water. I put some well water in there to help buffer the ph and to replace micros the ro water stripped out.
Water frequency: 2x times weekly. 2-3 gallons per plant. Top couple inches are usually dry.
Plants: 6 gorilla glue, 6 purple chem ( started as clones ). Currently 5-6' tall.
State: Pre-flowering.
Planted: Early May ( almost 3 months old ).
PH: Soil ph is 7-8. Water ph 6.3 to 6.5. Lately I've been using 6.0 in hopes of lowering the soil ph.
Nutes: GH Trio. 400-600 ppm. Calmag 2ml/gal.

Problems:

1) Yellowing leaves on the bottom of plant and some on the inner/middle of the plants. Leaves generally get depleted, crumble, and fall off. Which seems indicative of a Nitrogen deficiency.

Action:
Once I noticed the leaves turning yellow ( 3 weeks ago ) I started pumping the plants with nitrogen. They were yellowing pretty fast btw. GH trio was used at 5ml/gal grow, 5 ml/gal micro, and 1ml/gal bloom. PPM ~550; PH 6.5. After a couple weeks of this I noticed some plants had the 'claw', and there was also very minor tip burn on some leaves so I backed off. I watered only the next feeding, then I resumed nutes at rate noted above. Once started I went to a feed, feed, water regime.

I should note that prior to the yellowing I wan't feeding the plants much at all. Basically the first 2 months in the contains. I would Feed ( 1/3 dose ), and then Water the next time. Most of the plants did turn a lime green before this, so at first I think there really was a nitrogen deficiency. I was such a noob that I didn't recognize the problem before it happened. Lesson learned.

2) Not sure how to best describe this. The pic will describe it better than I can. It's almost like a rust (brown/yellow) on random areas on some lower leaves ( not all plants have this ). I first noticed this yesterday and thought it was mites or thrips. But I looked pretty closely with a 45x magnifying lens and I'm not seeing anything moving around. Maybe I'm dong this wrong though? I'm thinking it might be a PH issues?

Action:
I started flushing all the plants ( 5gal ph'd water [6.0 ] per plant ). On of the problems here is that my greenhouse is somewhat remote, and I can only transport 40-45 gallons at once - not to mention it takes a day or so to generate 40 gallons of RO water. That and my containers are so damn big. So I really don't know how I can accomplish a proper flush of 2x the container size ( 40 gallons per plant ). It would literally take weeks to do this.

Notes:
Despite the issues noted above, my plants seem to be growing vigorously ( possibly out of control; I'm literally running out of room ). The top 2/3 of the plants seem healthy and have a nice green look - not too light or dark.

Testing the soil ph has been an issue for me. I have one of those two prong sol probes that checks the ph ( plus light and moisture ), but it seems pretty unreliable. I also have done a slurry test on occasion ( 1:2; one part soil to 2 parts distilled water w/ ph of 7.0 ). This seems more reliable. Unfortunately I do not have pans under my containers because they are so damn big ( 20g), so I don't know how to test the runoff ph. Btw my greenhouse sits on a crushed limestone foundation so runoff goes right through the floor.

As noted above, this is my first grow and I may be me overreacting a bit. But there are issues for sure. I'm hoping to prevent the issues from getting any worse, and I also would like to learn from this and prevent it from happening in the future.

Any help would be greatly appreciated. Thank you for reading my post. I tried to be as concise as I could :)
 

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Pbass

Well-Known Member
Hiya @ColonelBlake I've burned 'em just exactly like that. I'm no expert and I'm sure the big pot brains will show up soon, but I was able to steady my PH pretty early on, so the second time it happened, I attributed it to Cal/Mag in the end, some more of my agressive growers seem to need a bigger dose. I would also say you might try and work on getting that PH down in your soil. My Water PH is 7 by itself, soil would run around 7.8, which is not good. I use 4tsp of vinegar to every gallon which takes me to mid 6's that leaves my soil around 7. I rarely see the burn like that or nutrient uptake issues anymore. Cheers mate, GL to your grow!:yahoo:
 

Pbass

Well-Known Member
After looking back through your excellent account, I bet what happened is your PH got whacky resulting in the cal mag the cal mag not getting taken up very well, you started to burn stuff with the extra N.

Also I have a feeling that this might be caused by overwatering. You should be letting those plants get REALLY REALLY REALLY dry before you reapply. That alone could be causing your lockout.
 
Thanks for the input Mate!

Calmag is the one thing that i've used every watering for the last 3 months ( except for the partial flush that I did yesterday ). Application rate: 2mg/gal. Maybe you're onto something here.
 

Pbass

Well-Known Member
I'm not sure how much 2mg/gal is ColonelBlake and whether dry is different from wet but if I use a online calculator, it says I'm using 12500mg/gal. I use two tablespoons per gal, actually lately probably more like 2.5.

EDIT: DOH! Teaspoons not tablespoons. That calculation of 12500mg/gallon is for teaspoons still however.
 
I'm not sure how much 2mg/gal is ColonelBlake and whether dry is different from wet but if I use a online calculator, it says I'm using 12500mg/gal. I use two tablespoons per gal, actually lately probably more like 2.5.
I'm using Bloom City Cal-Mag, and the label says to use 2-4ml/gal in veg. So I'm at the low end of it. I only use it b/c I'm using 80% RO water. Maybe it's not necessary though since 20% of my water comes from my well. It's very hard water (450ppm) and has allot of calcium carbonate in it. I dunno. The more I read about growing the less I seem to understand.
 

Pbass

Well-Known Member
One of the very common things we see here with new growers (me being one of them) is overwatering problems. Alot of my early problems I can attribute to overwatering. People get on a schedule based on what they think the plants need but don't necessarily pay attention to the actual need on a day to day basis. They stay too wet and result in various bad outcomes.

There's a great watering piece (among other topics) here by @Emilya I don't have her link but you can search her, she's Pot Yoda. Now I let my plants go so bone dry they are sometimes wilting before I water them. I can tell how dry they are mostly by pot weight, but nowadays I just look at the drain holes on my 5 gallons. If they are bone dry down there, time for a drink!
 

Nunyabiz

Well-Known Member
Only mistake I see is you're are trying to grow a full blown plantation of plants for your first grow.

And hundreds of gallons of soil but no easily accessible water supply.

Nothing wrong with 20 gallon fabric pots, especially for outdoor plants that get this big, in fact it's the only reason you aren't having far more problems.
I dont see any real problems actually.
Are you only seeing just a few leaves that look like that only on the bottoms of 8' tall plants in a greenhouse in the middle of summer?
They look very good overall.
Be thankful you planted them in 20 gallon fabric pots.

Your only mistake other than trying to do too much on first grow was not going totally organic.
You should have let all that soil work for you, inoculate with mycorrhazae, added some amendments to it prior to planting and then all you would need to do is just water, no worries about pH, or under or over feeding.
In this situation I would have just put a simple filter on the end of a hose to filter out most impurities and chlorine and watered with sprouted seed tea and compost tea and you're good to grow.
 
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One of the very common things we see here with new growers (me being one of them) is overwatering problems. Alot of my early problems I can attribute to overwatering. People get on a schedule based on what they think the plants need but don't necessarily pay attention to the actual need on a day to day basis. They stay too wet and result in various bad outcomes.

There's a great watering piece (among other topics) here by @Emilya I don't have her link but you can search her, she's Pot Yoda. Now I let my plants go so bone dry they are sometimes wilting before I water them. I can tell how dry they are mostly by pot weight, but nowadays I just look at the drain holes on my 5 gallons. If they are bone dry down there, time for a drink!
Gotcha. I've actually read that post. It's a great article for sure.

For the first couple of months I was really good about watering. I'd wait quite awhile before I watered ( one a week usually ). Then when leaves started yellowing I kind of freaked out and thought that I needed to get them nutes on a more frequent basis. They were getting big by this point ( 4'+ ) and I thought they just needed more food.

It's really hard for me to tell when they need watering. Lifting the pot is pretty difficult since they are 20g pots, and under multiple scrog nets ( and a very tight area ). Usually I stick my finger all the way in the soil and if it's dry I will water. That being said I haven't done so the past few weeks. It's pretty much every 3-4 days.
 
Only mistake I see is you're are trying to grow a full blown plantation of plants for your first grow.

And hundreds of gallons of soil but no easily accessible water supply.

Nothing wrong with 20 gallon fabric pots, especially for outdoor plants that get this big, in fact it's the only reason you aren't having far more problems.
I dont see any real problems actually.
Are you only seeing just a few leaves that look like that only on the bottoms of 8' tall plants in a greenhouse in the middle of summer?
They look very good overall.
Be thankful you planted them in 20 gallon fabric pots.

Your only mistake was not going totally organic.
Thank you for your reply!

On average I'd say 10-15 yellow(ing) leaves per plant. Mostly at the bottom, but some are in the middle of the plant towards the stalk. The rust like issue seems to be isolated to a few plants - as of now anyway.

It has been hot here ( Michigan ) 80-85 everyday. They get 5-6 hours of sun. My greenhouse has a decent exhaust fan, a floor fan, and an oscillating fan that run whenever it gets above 75. There are 5 auto opening vents on top as well. But it still can get hot in there - possibly a few degrees hotter than ambient temperature.
 

Emilya

Member of the Month: Mar 2019
You really need to get a handle on this watering thing and let them dry down to the bottom of the containers in veg. Since sticking your finger in the top 3 or 4 inches of a 20g pot isnt going to tell you much, you need a better tool. Thank goodness for old school gardening tricks!

Get you a nice soft wood dowel stick and use it as a dipstick to see where your water table is in those containers. A dipstick can help you to easily track the fall of the water table into the last inch of the container, and then you will know when it is time to water. Going by a set time schedule of watering every so many days is NOT the way to do this thing... you need to adjust to what the plants need instead. Watch your wet/dry cycle and track it on a chart, and you will then know which plants are thriving by needing water every 2 or 3 days vs one that is struggling that takes a week to drain the container. Also, never let a plant in a huge container go more than 3 days without giving the top spreader roots a mini watering... just enough to soak into the first 3 or 4 inches... you know... where your finger was checking things out. As it turns out, your finger method does have a purpose, but it is specific to the top roots that you are fingering, and not indicating a need for a complete, or as I say, a proper watering.
 

Nunyabiz

Well-Known Member
Big plants like that and hitting close to 90 if they didn't have the root system they have because of 20 gallon fabric pots I can virtually guarantee that what small problems you're seeing here would be 10x worse if they were in something like 5 gallon buckets.
That amount of soil gives the plants a buffer for small mistakes and big plants need big roots to support them especially when they start to flower.

Frankly for your first grow and that many plants in a greenhouse in the summer I think you've done a phenomenal job for them to look this good.

I'd make sure they get as much airflow as possible.
 
You really need to get a handle on this watering thing and let them dry down to the bottom of the containers in veg. Since sticking your finger in the top 3 or 4 inches of a 20g pot isnt going to tell you much, you need a better tool. Thank goodness for old school gardening tricks!

Get you a nice soft wood dowel stick and use it as a dipstick to see where your water table is in those containers. A dipstick can help you to easily track the fall of the water table into the last inch of the container, and then you will know when it is time to water. Going by a set time schedule of watering every so many days is NOT the way to do this thing... you need to adjust to what the plants need instead. Watch your wet/dry cycle and track it on a chart, and you will then know which plants are thriving by needing water every 2 or 3 days vs one that is struggling that takes a week to drain the container. Also, never let a plant in a huge container go more than 3 days without giving the top spreader roots a mini watering... just enough to soak into the first 3 or 4 inches... you know... where your finger was checking things out. As it turns out, your finger method does have a purpose, but it is specific to the top roots that you are fingering, and not indicating a need for a complete, or as I say, a proper watering.
Thank you so much for your response Emilya! I will do exactly what you advised.
 
Big plants like that and hitting close to 90 if they didn't have the root system they have because of 20 gallon fabric pots I can virtually guarantee that what small problems you're seeing here would be 10x worse if they were in something like 5 gallon buckets.
That amount of soil gives the plants a buffer for small mistakes and big plants need big roots to support them especially when they start to flower.

Frankly for your first grow and that many plants in a greenhouse in the summer I think you've done a phenomenal job for them to look this good.

I'd make sure they get as much airflow as possible.
Thanks again for your input! Next year I will go fully organic as you recommended. I was thinking about using coco next year with smaller pots ( 5-10g ), but I don't think I'm ready for that.
 

Pbass

Well-Known Member
I don't concern myself about the organic/non organic thing. I don't do it in my daily life, and I haven't read anywhere that yield and quality is significantly improved. I'd be curious to hear if there are benefits to a grow beyond just producing a organic outcome.

One other thing....if you don't worry about the outcome, you're ready for anything!
 
I don't concern myself about the organic/non organic thing. I don't do it in my daily life, and I haven't read anywhere that yield and quality is significantly improved. I'd be curious to hear if there are benefits to a grow beyond just producing a organic outcome.

One other thing....if you don't worry about the outcome, you're ready for anything!
The biggest perk to me in regards to growing organically is not having to worry about flushing plants ( given my scenario - 20g pots, remote water location ). The other benefits are nice too. Including not having to add nutes and having a better tasting smoke. I'm not sure if it yields as much as non-organic growing. I guess I'll find out next year :)
 

Emilya

Member of the Month: Mar 2019
I will chime in on the organic vs synthetic argument @Pbass. There are still lots of things we don't understand about these plants, and feeding out of a bottle is only going to be as good as that understanding. Nature is superior to us in most ways, and the microbe's ability to feed the plants exactly what they need in an organic grow does make a huge difference in the plant's ability to fully express itself. You can read it here for the first time, organically grown pot does taste better and hits harder than synthetically grown pot.
 
You really need to get a handle on this watering thing and let them dry down to the bottom of the containers in veg. Since sticking your finger in the top 3 or 4 inches of a 20g pot isnt going to tell you much, you need a better tool. Thank goodness for old school gardening tricks!

Get you a nice soft wood dowel stick and use it as a dipstick to see where your water table is in those containers. A dipstick can help you to easily track the fall of the water table into the last inch of the container, and then you will know when it is time to water. Going by a set time schedule of watering every so many days is NOT the way to do this thing... you need to adjust to what the plants need instead. Watch your wet/dry cycle and track it on a chart, and you will then know which plants are thriving by needing water every 2 or 3 days vs one that is struggling that takes a week to drain the container. Also, never let a plant in a huge container go more than 3 days without giving the top spreader roots a mini watering... just enough to soak into the first 3 or 4 inches... you know... where your finger was checking things out. As it turns out, your finger method does have a purpose, but it is specific to the top roots that you are fingering, and not indicating a need for a complete, or as I say, a proper watering.
Summary: Sounds like your fingering isnt getting the job done! You need to use a long wooden dowel to make sure these girls are the right amount of wet.
 

Nunyabiz

Well-Known Member
I don't concern myself about the organic/non organic thing. I don't do it in my daily life, and I haven't read anywhere that yield and quality is significantly improved. I'd be curious to hear if there are benefits to a grow beyond just producing a organic outcome.

One other thing....if you don't worry about the outcome, you're ready for anything!
The yield if done correctly on the 2nd and beyond grow on the same soil is about equal.
The quality however is far better, organic soil grows give far better terpene profile and better trichome production.

I just finished harvesting 17oz from two plants, indoor under 600w of 4 year old Blurple lights.
From everything I've seen on the numerous grows on this site using any method that 8.5oz per plant is easily in the top 5 to 10% of yield.
If I had better lights I think I'd hit an average of 10oz per plant pretty easily.

And that's watering with nothing but sprouted seed teas, coconut water, aloe vera.
 
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