First grow, comments and diagnoses greatly appreciated!

I've got nine plants in smartpots w/coco on a drain table, started from seed about three weeks ago. I'm drip feeding the plants for fifteen minutes three times a day out of a (soon to be expanded) five-gallon reservoir. I'm using Canna brand nutrients with the schedule tool at http://www.cannagardening.com/growguide. The pH is around 6.0 and daily temps range 72F - 84F. Lighting is from four 3500K COB LEDs about 18" above the plants.

All the plants are growing but none of them appear to be doing really well. If anyone could comment on the pics below it would be greatly appreciated. I've looked at a lot of pics of problem symptoms but I'm having trouble really matching them up with what I see on my plants.

Two Dream Machines. One appears to be okay (?), while the other recently developed dead spots on her leaves:


Close up of the spotted one:


Strawberry Sour Diesel. Leaves are curling under somewhat, but no spots:


NL5 Haze Mists. Edges are curling upward somewhat, and maybe some dead spots on the tips?


Tangerine Dreams. Leaves are curling up a bit and also look a bit yellow in patches.


Jack Herer and Pakistan Valley. Neither of these started off very well but they're hanging in there.


Thanks for taking the time to look these over.

What's your ph? Both of your watering and run off.

Mr.Goodtimes said:

What's your ph? Both of your watering and run off.

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I'm glad you asked that! Last time I checked the pH it was around 6.5 and I added a tiny amount of pH down (like a teaspoon) thinking that it would bump it down maybe to 6.0. I should have checked it then though, because just that little bit of down sent the pH below 5.0! I dumped the reservoir and refilled it with four gallons of water from a distiller and four gallons from tap (fairly hard wellwater). I added 50mL of A and B and 75ml of rhizo which is 'light' concentration according to the Canna docs. I also added a tiny amount of pH down to get the pH to 6.0. I rinsed all the pots with this new mixture. The plants were receiving the bad mix for a total of about 24 hours. Here's hoping I didn't damage the roots too much.

After 24 hours on the fresh mix, the spotty plant is looking spottier, but the other plants are all about the same. Is it possible that the low pH could have caused the spots in a single day? And I wonder why just one plant was affected so much?

keep your ph in check, it's your 1 grow, I advice against doing things by feeling, you dont have the experience, not yet, your ph meter is your best friend, use it!
good luck and happy growing

how much A/B are you adding per litre of water, if you go by the canna guide you will kill them

Well, I made some changes based on all of your suggestions and things are looking up. Here's that spotted Dream Machine five days later:



Lots of new leaves, no more freckles on this girl!

I dumped the reservoir and thoroughly scrubbed it clean. The whole inside was covered with a slippery foul-smelling film, no idea where that came from.
I refilled with water from a distiller, added a light amount of Canna A, B, and Rhizo, a capful of CALiMAGic, and pH down to 6.0. I also started checking and correcting the pH twice a day, using a dropper to add pH down now because the instructions on the back of the bottle call for way too much.

I also noticed that the coco was soggy on some of the plants. I originally built the table planning on flooding, so I just switched the pump over to the flood pipe and now I'm flooding to about 1.5" every four hours and about 0.25" every thirty minutes. This seems to keep the coco wet but not soggy and also keeps the roots coming out the bottom of the smart pots wet.

Every plant is showing healthy new growth, even that sad Sour Diesel I had just about given up on.

Thanks for the advice all, I'm so glad I found this forum.

Heat/light stress, slight overwatering, needs Mg and probably N pretty soon.

Goggles said:

Well, I made some changes based on all of your suggestions and things are looking up. Here's that spotted Dream Machine five days later:

Lots of new leaves, no more freckles on this girl!

I dumped the reservoir and thoroughly scrubbed it clean. The whole inside was covered with a slippery foul-smelling film, no idea where that came from.
I refilled with water from a distiller, added a light amount of Canna A, B, and Rhizo, a capful of CALiMAGic, and pH down to 6.0. I also started checking and correcting the pH twice a day, using a dropper to add pH down now because the instructions on the back of the bottle call for way too much.

I also noticed that the coco was soggy on some of the plants. I originally built the table planning on flooding, so I just switched the pump over to the flood pipe and now I'm flooding to about 1.5" every four hours and about 0.25" every thirty minutes. This seems to keep the coco wet but not soggy and also keeps the roots coming out the bottom of the smart pots wet.

Every plant is showing healthy new growth, even that sad Sour Diesel I had just about given up on.

Thanks for the advice all, I'm so glad I found this forum.

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Needs nitrogen and you splashed water on it. That's what those spots are from. The water amplified the light and it got a little light bleached.

You might want to raise your lights to 24".

bobtokes said:

how much A/B are you adding per litre of water, if you go by the canna guide you will kill them

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I don't like to disagree with you bob, your a damn good chap when it comes to good advice. But I have used Cannas Coco range for the last 5 years per schedule on their website and never had any issues with killing my plants. I start on light feeding if its a new strain that I don't know well and then pump it up to normal, in some cases I use heavy and in the case of OG Kush I had to go above that. That is A+B, I never go heavy on boost or pk13/14.
It doesn't hurt to play on the safe side and go light and see how they react though.

@Goggles first thought was wtf how much ph down.. a teaspoon.. Use a drop at a time. Its strong stuff. I would be flushing my pots to make sure your ph is back to the correct range because it may take ages to sort its self out with a drip system. Then allowing them time to dry out so you know your roots are breathing. Meaning turn off your drip system and measure the time it takes to dry out. They are small plants in large containers and probably getting a bit too wet.
I think I would be hand watering to let the small ones catch up you can always flip your drips back on when they are back to good health and growing faster.

GL with them

coreywebster said:

I don't like to disagree with you bob, your a damn good chap when it comes to good advice. But I have used Cannas Coco range for the last 5 years per schedule on their website and never had any issues with killing my plants. I start on light feeding if its a new strain that I don't know well and then pump it up to normal, in some cases I use heavy and in the case of OG Kush I had to go above that. That is A+B, I never go heavy on boost or pk13/14.
It doesn't hurt to play on the safe side and go light and see how they react though.

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no probs mate, i've never used canna A,B at more than 2ml per litre myself, and with everything else i put in my feed, my E.C never goes much over 2.0 thats including the back ground of 0.5
when i first started using it at canna's recommended doses i got nitrogen toxicity in veg, so now i just supplement with 13/14 in flower 1/4 - 1/2 dose to balance things out.
i know a few people that have had this problem with canna a/b, and thats with hungry strains
but each to his own, lol

Can you post some pics with how old they are plz ty