Young plants are bright yellowish and grey spots are appearing on the leaves.

Water Ph: Always 5.8 with hydro.

1) I soaked little cubes in 1/4 of the dose of Canna Coco A+B + 4mg/1L of Rhizotonic.
2) Planted seeds and they sprouted in 4 days.
3) One week later I soaked 2.5" cubes in the same nutrient solution, but I lowered Rhizotonic to 2mg/1L.
4) Then transplanted little cubes into 2.3" cubes.
5) One week later I transplanted rock wool cubes into coco coir.
6) (Roots were coming out from the bottom of the cubes like crazy. Everything looked 100% awesome)
7) Then watered with 1/4 of the dose of Canna Coco A&B + 2mg/1L of Rhizotonic + 0,4mg/1L of Cal+Mag.

This is probably where I made a mistake number 1 of adding too much Cal+Mag???
.. and a mistake number 2 of giving almost 0% runoff???
.. and a mistake number 3 of letting the coco substrate get too dry???
Unfortunately it took me 5 days before I got them watered again and in these days I noticed my plants getting bright, almost yellowish green.. and in last few days I also noticed grey spots appearing in 1/3 of the plants.

This time I watered with the same nutrient solution as before, but I lowered Cal+Mag to 0,2mg/1L and gave them 20% runoff.

One day has passed, but nothing has changed except that now there are few more plants having the spots on their leaves...


Please help me. I'm worried. Plants are 3 weeks old.

Pictures will be uploaded in few hours!

So many mistakes hard to reply without tears in my eyes...avoid feeding nutes to seeds or seedlings until the plants are 2 weeks or or suffer the consequences ,,,sorry

can never understand why inexperienced growers always want to experiment on the plants time, when they don't have the experiences to understand their experiment

Flush and flush fast ...avoid nutes until plants are 2 weeks plus old

jondamon said:

With CANNA I use
4ml per litre Rhizotonic for seed starting and the first week after they pop. Along with A and B nutes made up to EC 0.6.

Then 2ml per litre Rhizotonic after that.

During flowering knock the Rhizotonic down to 0.5ml per litre.

Click to expand...

0,6 EC is 1/4 of the full dose.

They were doing very well until I transplanted into coco. I don't believe I did anything wrong before that.

They have been in coco for a week now.

So you're saying that I should flush?

jondamon said:

Then 2ml per litre Rhizotonic after that.

Click to expand...

Oh damn.. did he mean Rhizotonic ONLY after that??

vostok said:

So many mistakes hard to reply without tears in my eyes...avoid feeding nutes to seeds or seedlings until the plants are 2 weeks or or suffer the consequences ,,,sorry

can never understand why inexperienced growers always want to experiment on the plants time, when they don't have the experiences to understand their experiment

Flush and flush fast ...avoid nutes until plants are 2 weeks plus old

Click to expand...

Think you're wrong here. Plants need nutes from the beginning and he was in rockwool cubes. Maybe in soil you dont need to give nutes, but that is because the soil has its own nutes that can usually get the plants by for a week or 2.

OP, I would ignore all of this. Not sure what you're problem is, but its not overuse of nutes.

Thank you for your comment.

StanlySpedowski said:

Think you're wrong here. Plants need nutes from the beginning and he was in rockwool cubes. Maybe in soil you dont need to give nutes, but that is because the soil has its own nutes that can usually get the plants by for a week or 2.

OP, I would ignore all of this. Not sure what you're problem is, but its not overuse of nutes.

Click to expand...

I would most definitely ignore this totally incorrect assumption that this noobie is firing on ...seeds weather planted in soil, water(DWC) or fucking RW sponge need no food or nutritional supplements until the cotyledons have even developed, to most grow ops that 7-14 days at most, why feed a seed or seedling that has very little roots to absorb the nutes ...?

OP, I would ignore all of this. I know what your issue is, and here haste makes waste ...wait and see

1: soak you plant in the kitchen towl method see pic

2: once 4-6 inches (week 1)or so transfer to a bubbler or at least hydroton

3: little round leaves are fully developed(cotyledons) add quarter strength nute ..even that could be too strong consider your strain

It turns out that Canna Coco A&B that I'm using already has enough calcium and magnesium in it, so that calmag which I added was too much for my plants. I changed my nutrition solution to 4ml Rhizotonic per litre and 300PPM of Canna nutes and gave them 75% runoff.

May happen that I found a solution for my problem.

If this is how they looked yesterday, then let's see what tomorrow brings. Hopefully I'm right about it.

I stopped adding calmag, because it turned out that coco has a tendency to calcium and magnesium deficiency after about 6 weeks of use.

I gave them 75% runoff with 1/4 of the dose of Coco A&B (300ppm) + 4ml per litre of Rhizotonic.

It got better. New growth turned green and overall picture got better. Seemed like it fixed it.

But now I can see some spots reappearing. I'm not sure what are they indicating.

What do you think?

what is the EC of your tap water? reason i ask is you may need to add calmag to bring it to .4 for a base. Canna assumes you use water with a EC of .4, assuming also that is primarily cal and mag
newer rust spots and raised edges indicate calmag needed. older grey spots are from toxicity in the past.
you will do well to emulate jondaman. he gives good advice for coco
btw i think you made a good self analysis in you first post and you are back on track now

Thank you, but I'm using distilled water which has a PPM value of 0. Does it mean that EC is also 0 then?

You're saying I should add calmag?

Maybe Jondamon didn't know I'm using distilled water? Hmm....

yes. add calmag. full dose is 200ppm(.4 ec) try half of that first

I start with tap of .16ec so i add 4ml/L to mine. brings it up to .4ec.
certain strains need more

Although I've been told that coco has a tendency to calcium and magnesium deficiency only after about 6 weeks of use and I've been recommended to start adding calmag only when the first signs of deficiency appear.

P.S. Canna Coco A&B nutes which I'm using already have 5% Calcium and 2% Magnesium in it.