Struggle with seedlings/early veg in coco

Greetings coco growers!

I've been having problems with early stage plants in coco for the past 5-6 grows so finally I decided to post as I have been running out of ideas.

Plans on the pictures are in week 3, about 18 days since I places them in rootriot plugs. They are slow and some of them are literally dying. Not all are bad, but I can see that even the healthy onеs are slowly showing deficiencies.

Plants were started in Rootriot plugs @ 150-200ppm and were fine until they touched the coco.

• Media: Canna Coco Pro (pre buffered and pre washed) - Ph is 5.8-6, measures with Bluelab multimedia pen.
• Water source: 80ppm from the tab
• Nutes: Canna A+B, Rizo, Canna Calcium Mono + a bit Humic/Fulvic acids and Canazyme.
• Feeding light once a day between 350 and 400 ppm total, ph 5.8, pots are quite soaked at all times.
• Runoff with every feed. Runoff is the same as what goes in ~350ppm, ph as well.
• Daily Foilier feed - 2ml/l cal + 1ml/l rizotonic
• RH 70%, temps 23-24 degrees
• LED Lights - about 150 ppfd at the level of plants. Light is on the lower end. Recommended is 150-300 ppfd.

The previous batch of 20 plants died all, just like some of those will. The only difference is that I was feeding them 350-500ppm towards the end. Experience has showed me that more feed makes things worst. Also for those 20 I buffered the coco with 2ml/L for 24 hours, just in case.

First of all, could you confirm that this is a CalMag only issue? It looks like they can't get phosphorous, perhaps locked by the calmag def? Could it be calcium toxicity?

I am not new to growing, but I suppose I am missing something major enough to perpetually run into such trouble in coco.

Will appreciate help from coco growers.

Underfeeding is my guess.

But I can barely keep them alive myself. Someone decent like @hotrodharley will offer much better advice

Autofire said:

Underfeeding is my guess.

But I can barely keep them alive myself. Someone decent like @hotrodharley will offer much better advice

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Ask someone with coco experience. I had a thread blasting coco in general deleted within a day recently. I know it must be soaked and rinsed and then it’s suggested soaking in cal mag. And it requires mucho water.

Cost you about 5 bucks more per 12 gallon bag to buy the cannabis specific pre washed pre buffered stuff.

If you set your watering up right you shouldn't really use any more nute than any other hydro. It's hot where I live and there's no way I could keep my water temps down enough for DWC in summer. Plus I need to be able to walk away for a week and not have things go south.

I use Canna Coco Professional - probably the best on the market (prewashed and prebuffered) and some of the pots are actually in Polagron Premium, just to make sure it is not a batch/brand issue. Hope to hear from people who have actually battled this type of issue as it seems quite common for coco.

Autofire said:

Cost you about 5 bucks more per 12 gallon bag to buy the cannabis specific pre washed pre buffered stuff.

If you set your watering up right you shouldn't really use any more nute than any other hydro. It's hot where I live and there's no way I could keep my water temps down enough for DWC in summer. Plus I need to be able to walk away for a week and not have things go south.

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A pro here using it in a mix assures me it still needs soaking and rinsing.

I’m with you on the time away. Salmon start running. Halibut are biting. Last thing I need is a needy crop.

Your def nuking them with feed.

400ppm on the .5 chart is .8 ec.

Plus you are foliar feeding tiny plants.

Feed at .4ec for a lil bit. Wait till they get some foliage going before hitting them hard.

You gotta treat coco like hydro. Start low.

A lot of people never go above .8ec for the entire grow and you got your babies there now.

Cut the foliar feed for now. I like it before and during the stretch because I usually end up with a calc issue in the stretch if I don't.

If your going to foliar feed it should not be every day also.

Honestly, I've had trouble with coco during the early growth stage when I first started using it. At that stage you treat it a little more like soil, in that you need a wet/dry cycle to get the roots to fill out. You CAN overwater coco if the plants are small and the roots haven't filled out. 200-300 PPM is fine, but let them get almost dry...UNTIL the roots fill out those small containers, then pot up and start the process over again. Wet/dry(ish), never totally dry, until the roots fill out. Once the roots fill out you are good to go with multifeeding. If you let them get totally dry, the EC skyrockets and you risk burning your plants, but you can let them get a little dry without worrying about that while feeding a very low EC. GOOD LUCK

Failmore said:

Your def nuking them with feed.

400ppm on the .5 chart is .8 ec.

Plus you are foliar feeding tiny plants.

Feed at .4ec for a lil bit. Wait till they get some foliage going before hitting them hard.

You gotta treat coco like hydro. Start low.

A lot of people never go above .8ec for the entire grow and you got your babies there now.

Cut the foliar feed for now. I like it before and during the stretch because I usually end up with a calc issue in the stretch if I don't.

If your going to foliar feed it should not be every day also.

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Thanks for the reply. I also lean more towards the overfeeding case. Will follow your advice for both media feed and foilier feed. In the mean time I hope to get confirmation from more growers.

plan500 said:

Thanks for the reply. I also lean more towards the overfeeding case. Will follow your advice for both media feed and foilier feed. In the mean time I hope to get confirmation from more growers.

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Yeah if anything it is just the foliar feed. .8ec isn't crazy hi for small plants. But when you add in a foliar feed it is possible to much to handle.

Rurumo said:

Honestly, I've had trouble with coco during the early growth stage when I first started using it. At that stage you treat it a little more like soil, in that you need a wet/dry cycle to get the roots to fill out. You CAN overwater coco if the plants are small and the roots haven't filled out. 200-300 PPM is fine, but let them get almost dry...UNTIL the roots fill out those small containers, then pot up and start the process over again. Wet/dry(ish), never totally dry, until the roots fill out. Once the roots fill out you are good to go with multifeeding. If you let them get totally dry, the EC skyrockets and you risk burning your plants, but you can let them get a little dry without worrying about that while feeding a very low EC. GOOD LUCK

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I intentionally mentioned that they are constantly soaked. And now I realize that those cycles you suggest are actually more important (at early stage) than say the need to flush the media more often to replace oxygen, nutes and probably adjust the ph of the media.

Failmore said:

Yeah if anything it is just the foliar feed. .8ec isn't crazy hi for small plants. But when you add in a foliar feed it is possible to much to handle.

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Will cut foilier feed for sure.

plan500 said:

I intentionally mentioned that they are constantly soaked. And now I realize that those cycles you suggest are actually more important (at early stage) than say the need to flush the media more often and replace oxygen, nutes and probably adjusting the ph of the media.

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I did the same thing with my first coco grow. Don't worry, once they get some good roots on them, they'll be much easier to water.

Autofire said:

Cost you about 5 bucks more per 12 gallon bag to buy the cannabis specific pre washed pre buffered stuff.

If you set your watering up right you shouldn't really use any more nute than any other hydro. It's hot where I live and there's no way I could keep my water temps down enough for DWC in summer. Plus I need to be able to walk away for a week and not have things go south.

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I've been buying bricks of cheap coco for a long time and I'm almost positive everything on the shelves now is prewashed. I used to encounter bricks that still had high salt content but for the last 5 years or so they have all been good to go. The only difference between the bags and bricks of pure coco is the compression

Of possible help.

TintEastwood said:

Of possible help.

Seedlings and Clones in Coco, Week 1 - Percys Grow Room

There will be some differences in growth depending on if you started with seedlings or clones in coco. Find out about growth in week 1 of a coco grow.

percysgrowroom.com

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Thanks, this hits both overwatering and overfeeding. Plus it reminds me to change from 22 to 20 hours of light.