Soil conundrum!

[kungfubru]

Hi Guys

I'm new here and have a little problem that i hope some of you nice peeps can help me out with!!

I am using "Canna terra professional plus" soil, and the Canna Terra vega/flores nute range.

here is my issue, This soil is buffered to 5.8/6.2, on the nutrient bottles it says to aim for a ph of 5.8/6.2,,, ok cool,,, but isn't that a bit low for growing in soil?? The recommended EC levels seem a bit hot too...I have read around, and around.....aaaaand around,,, looked at various PH uptake charts and the general consensus is that when using Chemical nutrients the sweet spot is around 6.5.. I don't understand why a manufacturer would buffer a soil so low, especially "and if im correct in saying this" when the tendency is for the soil to become more acidic over time with salt build ups!? Same with the nutrients, why so low? It almost feels like this is more of a soil-less setup....

Thing is,,, i keep getting Ph issues!! To be honest I've always been to scared to follow the Canna guidelines, and plumbed for adjusting my feed down between 6.8 to 6.5 but i keep getting the same issues with the plants,, A couple of weeks into the main room around the time of flipping to 12/12 shows the start of multiple nutrient deff's N, Mag, Cal.. Mag seems the most prevalent, and the first to show in veg,,purpling on the branches, and leaf stems, spots on leaves. Pale new growth and yellowing older, although the lower part of the plants do seem to keep there green a little better, finishing with leaf die off in extreme cases.

Decided to do a flush this eve as they had started to look a bit pale, looked like they hadn't been feeding.... Flushed 15L pots with about 20L of water ph'd to 6.5, which brought my EC down from 1.9 in some cases to floating around 0.9/1.0... I have a pretty decent soil PH probe which after i flushed was reading just under 6.3, after leaving it in the soil for 30 mins or so it had normalized back to 6.2 as per the manufacturers guidelines!!

My Tap water is OK but not amazing,, PH can fluctuate a bit, had it up to 8.2 in the summer but usually it floats around mid to upper 7's and it has a background EC of 0.5..

So been thinking about maybe adding a little extra Dolomite lime to my next soil mix, or maybe even sprinkling some over the tops of the ones on the go right now,, Would that be something thats good to do??

If anything jumps out that im doing incorrectly them im open to some advise,,

thanks for reading,,,, errr bit long sorry!!

KFB

 

[Spimp]

I could be mistaken but I think you are way over analyzing your soil. If you feed with correctl ph'd water it will slowly raise the ph to where you want it.

Plants excrete ions as a waste product and this regulates the soil PH. So as long as you have a living plant in the soil, you will not be able to Control to the decimal your PH. If you constantly tinker and flush trying to get the soil to a specific PH, your plants will give off more ions and cancel your actions while being deficient from all the flushing.

Water 'in the range' an check runoff PH. If its not too drasticly above or below, its where it should be. Soil is a different medium from Hydro where th PH has to be exact. As long as the stuff going in is in range, the sil will buffer the ph and your MJ will help control pH.

If you have extreme numbers high or low, than measures should be taken. But if your runoff is somewhere between lets say 6.9 and 5.9, dont stress. Flower PH can lockout nutes if below 6, but nutrients in soil are absorbed in very wide ranges.

 

[kungfubru]

Hey spimp,, thanks for your reply,, i would agree with the over analyzing, but sometimes it's necessary to get things straight,,, in MY head anyway haha...

anywho,,,,, Here is a response i got from one of Cannas in-house horticulturist, found it very informative and thought i would share it with yourself and anyone who may be having similar problems, or have similar questions about what is soil and what is a "Potting mix" and how to deal with a potting mix,,,

CANNAS HORTICULTURIST ANSWERS ARE IN GREEN


I got a quick response from our horticulturist from your first email that I sent him I will highlight the answer to your questions in green

I'm having issues with identifying your growing medium, Am i to treat it as soil or soil-less or somewhere between the two?? The guy at my hydro shop insists it's a soil and that i should feed according to a soil regime yet the canna site never actually describes "terra proff plus" as a soil, they call it a potting mix.

Soil is mother Earth and actually you cannot buy it. Outdoor growing is often done in soil
A potting mix is made of peat. A lot of people call this soil although it is a potting mix
Every Brand makes his own mix, so you cannot always compare them because they are not the same.

The reason for asking is that it seems after hours of reading that the sweet spot in soil, for what i am growing, is around 6.5 (where NPK and micro nutrients are most available)

Nutrient are the best solvable between 5,2 and 6,2. But....
Terra, our potting mix is made of peat which has a pH of 3,5 - 4,0. In that pH your sweet spot will not grow. So we add chalk (lime) to it and make a pH of 6,1 (+/- 0,2)
Giving a lower pH (with the water) will break the chalk down, so don't do it.
A higher pH makes a few nutrient elements less solvable, which means less absorbable for the plant

The best is to give a pH between 5,8 and 6,2 to our Terra.

Yet canna terra professional plus (which is what i am using) is buffered to around 5.8/6.2 and the canna terra vega/flores should be PH'd to 5.8/6.2 also.

Correct.

So what's going through my mind is that at this PH range i am locking out certain nutrients.

No you don't. Not the elements which are in the water between the peat veins, which a root can take
Yes they block in the veins, but these are not available for the roots for that moment.

Subsequently i have been ph'ing my nutrient solution at around 6.5 /6.6 right from the first feeding in veg.

That is to high.
That means some elements like metals Iron Magnesium Manganese cannot be taken, which are needed to make Chlorophyll, which makes the plant green.
You will see light green leaves especially in the top(Fe), but even yellow spots later on in the middle part (Mg/Mn)

By giving extra N27% often the problem solves, because this nutrient will bring the pH down in the substrate (not in the water)
Some Brands make use of this N27% in their nutrient and do recommend a high pH.
A dangerous recommendation, because later on the plant will take the pH down in the rootzone, when the plant start to flower.
According to us; the mistake was in giving a high or (wrong) pH,

If i am completely wrong in doing this i will hold my hands up, having said that i am interested in knowing the mechanism as to how the Canna PH guidelines for soil and nutrients work, and how at that particular PH range you can still make all the goodness available to the plants.

My tap water is not the best but don't think it's the worst either,, I have a Background EC of 0.4/0.5 and the PH is around 7.4.

Indeed this is normal water

I let it stand for 24hours or so and bubble it too, although i may stop this as it has a tendency to push the PH up even higher.

Bubble the water until it is on temperature. Then make the nutrient and correct the pH. Don't bubble anymore after that.
And then give it to the plant. So try to make only a stock of 1 water supply. It is the most simple and free of pH problems.

I'm indoor growing, room temps are 78C lights on and around 70C lights off, with a RH of around 55/60% give or take, i have good air circulation and x3 600w HPS(air cooled) in a floor space of around 5sqm,

So 1800W / 5 sqm = 360 W/m2,
I hope you use wide spreader reflectors
and your potential could be around 360-400 gr./sqm

i have lights around 2 1/2ft away from the tops of plants seeing as i have quite a bit of light, plants don't stretch, so im seeing this a good sign that they aren't too far away.


Plant problems seem to start fairly early in Veg, with what looks like a Mag. deficiency(purple stalks, spotting on leaves etc)

Purple stalks is also an indication of high pH.

then when pot up and move into the main room things look really good for a week or so,

In the first week they get nutrients again of the new soil with a right pH. But you make in impossible again within a week to take it later on by giving a high pH.

then multiple deficiency signs start to appear, growth seems to slow down, tops of plants start to take on a limey green tinge while the bottom of plants tend to stay green and healthy looking(which i believe are signs of Cal. issues) then they progressively get paler and paler looking like a nitrogen deficiency. Plants seem to stop feeding as checking the runoff from a pure water flush produces readings of around 2.0EC and i'm only feeding them at 0.9/1.1( seeing as i don't grow monster plants) so i know there is a build up.

If you give feeding (even when it is low) and the plant cannot take it by the high pH, these nutrient will be build up in the substrate.
Again an indication your pH is to high.

Some leaves then start to die off, this process starts with them going yellow with spots and then they drop off.

The leaves are not building up properly because their is a lack of certain elements. So they die off quite fast.

Also i use a feed then water cycle.

so after ALL THAT,,,,,, i guess what i'd like to know is, is "terra proff plus" a soil or soil-less and can i safely go by the PH recommendations on my nutrients (sounds stupid to ask seeing as it's on the bloody bottle). Also,, are there different ranges of nutrient PH which i should be aiming for at various stages of growth. i.e

early veg pH 5,8
full veg, pH 5,9
early flower pH 6,0,
late flower. pH 6,2 (when PK is given)


On a side note my plants never look as good as when i pot up and just give plain ph'd + rhizo for the first week or so, i do plain water due to the charge in the new soil..... My problems seem to arise when i start feeding them myself.

We think your problems start when you start watering (with no or to little pH correction)

Also I am currently just over one week into flower!!!

So change the pH to 5,8
Give temporarily (2-3 weeks) N27%, to cure the problem

I hope this information makes things clearer for you if you have anymore questions then ping me email and I will get back to you

 

[MrGreeny]

early veg pH 5,8
full veg, pH 5,9
early flower pH 6,0,
late flower. pH 6,2 (when PK is given)

Hi Op
Reading your post was like a blast from the past for me.

I had the exact same issues with the same soil. I searched and read endlessly for the answer but could not find it. I had my ph perfect at 6.5 for my soil of course.....
I combated the buffered 5.8 ph it came with and always used lime and PH uppers to get it to 6.5.
Why would a manufacturer make the PH so low!! This was my problem all along.
Then luckily a fellow poster (on another board) spotted my error. Dozens had tried to help, but none were aware that Canna Terra Pro Plus is classed more as a soiless mix rather than a soil. I never read this anywhere else.

As soon as I treated the soil as a soiless (using a Ph of 5.8), Everything immediately fixed itself.
The two grow shops I used never knew of soiless classification of the terra Pro plus either. They had been advising their clients for years incorrectly to use a 6.5 PH

I just wanted to share this experience with you, you were not alone in the obscurity. Fair play to you for emailing them directly and for posting the solution. I'm sure it will help many others.

As for your last remark with PHs, Yes starting at a 5.8 and slowly moving to a 6.1/2 will help move the range of the nutrient into a optimal window for the different stages, another bonus of that is I also find the increasing PH helps combat the gradual reduction in PH that builds over the months from all the ferts.

Well done on finding your solution to your tricky problem.

Mgy

 

[Calvados]

This is an excellent thread. I have passed it on many times.

 

[Boris Parlov]

Thank god I found/searched for this.

I've done two grows using Canna Terra Professional Soil, and autoflower seeds from FastBuds. During the first grow I fed them straight tap water (pH 7) and had many problems. I still got a decent yield from 3 plants, but nothing like I see other people getting.

Second grow I started using a analogue pH meter that seemed to be working well. But I was having the same problems as the first grow. I started pH the water to between 6 and 6.5, but the problems stayed.

Then I got a cheap digital pH pen. I did a test of some water that was reading 5 on the analogue meter. It was 3 with the new digital meter!

Now that I've found this, I'm feeding my third grow water that is pH'd to around 6.1-6.2 (they are 7 weeks in) and I'll follow the full pH guidelines for my next grow.

I've barely used nutrients during the third grow, as I figured they were just adding to my problems. But my problem all along was using the wrong pH levels for watering.

Can't wait for my fourth grow!!!

Any suggestions regarding re-using the current "soil" for my next grow? I threw away my last batch because I thought it was too hot.

 

[SmokingWings]

Any suggestions regarding re-using the current "soil" for my next grow? I threw away my last batch because I thought it was too hot.

Why would it have been "too hot"?

 

[Keffka]

Any suggestions regarding re-using the current "soil" for my next grow? I threw away my last batch because I thought it was too hot.

Make sure to answer @SmokingWings question as well since that will help inform, however this will really depend on what nutrients you’ve used in the soil and whether or not you’ve had pests/bad fungus/mold/etc.

If you’ve been using synthetic or chelated nutrients you’ll likely struggle with reusing the soil. You can do it but the amount of effort and resources to revitalize it would likely be better spent on new soil with the goal in mind of reusing it.

If you’ve been using organic amendments with no organic acids or chelators you’ll be in perfect shape to reuse. Cannabis actually grows better when you reuse soil. It grows even better when you use the same strain and same soil.

Without launching into a huge biology lesson, the basics are, cannabis likes specific microbes and will cultivate an environment suitable for the ratios of microbes it prefers. Each strain has its own preferences so if you can grow the same strain in the same soil, you’ll get really good results. You can use other strains too, it’s not a big deal, you just won’t see the same improvements.

Some soils can go for 2-3 grows before needing to be revitalized. Revitalizing is just a matter of adding some of the minerals back into the soil and ensuring good carbon ratios. This is much easier than it sounds but it does require quite a few up front purchases that will last you a few grows at least.

 

[Boris Parlov]

Why would it have been "too hot"?

I used a fair load of nutes during that first grow, then discovered the "soil" contains NPK to a ratio of 12/14/24.

I thought with the nutes in the "soil", the nutes I'd added and the pH problems that existed I'd be better of starting with a fresh batch.

My understanding now it to re-use the medium I can treat it with Cannazyme.

Nutrients and additives I've used/am using:
Canna Rhizatonic
Canna Cannazym
Bio Diesel Aloevate
Growth Tech Complete Focus
Bio Diesel CalMag
Canna Bio Vega
Canna Bio Flores
Bio Diesel Bloom
Bio Diesel Rhino K

To confirm, I'm in Oz and this is the product:

Canna Terra Professional Soil 50L, Aqua Gardening

Ready to buy Canna Terra Professional Soil, 50L. With high value organic ingredients such as airy peat moss and tree bark, Canna Terra provides antiseptic properties. Canna Terra Professional Soil 50L Fastest Shipping in Australia. Buy online at Aqua Gardening aquagardening.com.au 07 3354 1588

www.aquagardening.com.au

 

[SmokingWings]

I used a fair load of nutes during that first grow, then discovered the "soil" contains NPK to a ratio of 12/14/24.

Do you have the name of that soil? Those sound more like fertilizer numbers. We often find soils and worm castings to have NPK numbers that are much, much lower.

 

[Boris Parlov]

Do you have the name of that soil? Those sound more like fertilizer numbers. We often find soils and worm castings to have NPK numbers that are much, much lower.

That's 'Canna Terra Professional Soil' (Australian version). This info is at the bottom of the product page.

Directions for Watering Canna Terra Professional​

Feature	Value
Use	House, terrace, border, balcony plant and Perennials.
Ingredients	Peat, Perlite, Dolomitic Lime, Mineral NPK Fertiliser
Dry Matter (% of the product weight)	>30%
Organic Matter	>85%
Electric Conductivity (EC)	1.0 mS/cm
pH (water) Zone	6.0
Mineral fertiliser NPK 12-14-24	1.5 kg/m²
Volume (in accordance with standard EN 12580)	50L

 

[SmokingWings]

That looks like the NPK of the fertilizer added to the soil mix. Once added it is diluted down by the rest of the soil mix. I really doubt that it is the NPK of the soil mix itself.

Also, once you have had one grow with that soil some of that fertilizer was used up so the remaining fertilizer would be reduced as compared to when the soil was brand new.

 

[Boris Parlov]

That looks like the NPK of the fertilizer added to the soil mix. Once added it is diluted down by the rest of the soil mix. I really doubt that it is the NPK of the soil mix itself.

Also, once you have had one grow with that soil some of that fertilizer was used up so the remaining fertilizer would be reduced as compared to when the soil was brand new.

Do you think the added NPK fertilizer makes pH management more difficult? 1.5kg per square metre sounds like a fair dose?

I've got some plants that have about 3 weeks to go then I can start another run (photo attached). I want to make sure I'm doing the right thing this time as it's my fourth run. So I've got a Bluelabs pH pen so that I have an accurate tool to help me get pH levels right for water/nutes.

I'm planning on res-using the "Canna Terra Professional Soil" with a bit of added Coco/Perlite. It says on the product information "Use a second, third, and fourth time when combining with Cannazym or Bloom Organic Sweetener." I have Cannazym, so I plan on doing what Canna says to do.

I understand the added NPK nutrients will have diminished after the growing medium has been used once. I think that's probably good, as the autoflowers I grow don't seem to require a lot of nutrients/are very easy to over feed.

 

[SmokingWings]

Do you think the added NPK fertilizer makes pH management more difficult?

No.

1.5kg per square metre sounds like a fair dose?

I am wondering if that is an error. Without knowing how deep the soil mix is it seems like 1.5 kg is a lot. The square meter is just the surface area, how much soil is under that surface? Maybe they meant per cubic meter or m3.

 

[Boris Parlov]

Yes me too. I'm not even sure that they measure "soil" in square metres. I'm no scholar but I assumed they meant cubic.

Either way I'm going to set up one pot with an alternative medium to Canna Terra Professional to see what happens.

 

[Boris Parlov]

I'm back. I finally gave up on Canna Terra Professional Soil after 4 frustrating grows.

I'm using "Turbodirt" from Dr Greenthumbs (Australia). It is a fully organic living soil blend. It is sold as water only soil, but there are additives that need to be used to keep the soil healthy.

Dr Greenthumbs TurboDirt Water Only Super Soil (27L / 70L Bags)

Dr Greenthumbs TurboDirt: 100% organic living soil for mineral-rich, nutrient-dense fruits and flowers. Ready to use with built-in plant nutrition. Inoculate with Root Roids and Fruit Roids for optimal results. Ready to use super soil!

www.drgreenthumbs.com.au

I have a soon to be 7 week old Grandaddy Purple auto in the tent...and it is lush and green! No pH issues/no nutrient lockout etc.

I also have 1 Apricot and 3 OG Kush autos ranging from 7-14 days. I can't wait to see the results!

 

[Calvados]

I use canna terra pro plus as well. Sorry I missed your struggles. I've just recently returned for my 5th grow.

Looking forward to seeing how your new soil works out. Best of luck.

 

[Boris Parlov]

All good. I can't find a list of ingredients for Canna Terra Pro Plus, which appears to be the product name overseas. In Australia it's just Canna Terra Professional Soil. But I imagine they have exactly the same ingredients.

I did everything as directed including pH etc. But something kept going wrong. The Bluelabs pH pen was a big investment and slightly improved things, but I figured I was going to keep running into the same problems, and really needed to try another medium for my own sanity.

The new soil seems to be pushing the plants into flower early. The Apricot Auto is only 19 days old but starting to show tiny pistils. The Granddaddy Purple auto started flowering at 3 weeks.

I think in the long run it won't matter, as the plants won't be going through any distress in this medium, and will be constantly growing during their whole lifecycle. With the Canna soil, I'm pretty sure growth was being stalled once or twice during the grow. Any LST or topping was just adding to the distress/slow growth.

I've definitely learned a lot! I'll start a thread in the Autoflower section to show progress.

Thanks.