Problem with young plants

Spirit Cloud Star Chaser · Feb 18, 2019

Hey Everyone, please help young plants are dying. It started out as dark spots then started drying up and going crispy. They're in air pots with coco & perlite. I'm using advanced nutrients sensi coco grow (half strength) and superthrive. Coco is always moist but never saturated. I have attached photos for better diagnosis.. please help before it dies. Cheers everyone.

CannaCountry · Feb 18, 2019

You're going to need to provide your grow details...the more details the easier it will be to figure out the issue at hand.

Temps, Relative Humidity, how often do you feed, do you water with straight water at any point, do you allow the coco to dry out between feeding / watering, did you rinse and buffer your coco before you used it, are you pH'ing your feed / water and if so to what....these are all important questions to know.

Hugo Phurst · Feb 18, 2019

How long have you been feeding them?
IMO - A seedling doesn't need to be fed until the cotyledon starts to fade/curl

3rd Monkey · Feb 18, 2019

I'm going with ph but a white light pic would really help.

Looks like ph or calmag.

I don't know if there's a cal supplement in those nutes. This was not an overnight thing though. Being as they are that young, I'm guessing ph.

sadanimalknight · Feb 18, 2019

Looks like PH curl to me.

Having your ph off will affect the uptake of nutes.

Check PH of the runoff and let us know.

Did you buffer your coco with calmag before planting?

Spirit Cloud Star Chaser · Feb 18, 2019

RH 60%
Temp 27c
Feed 1 hour after lights on and 2 hour before lights out. I don't let it completely dry out as I've read it's not good for coco but it isn't soaking. I didn't rinse or buffer my coco, supposable it had already been done (Nutriefield premium coco). I do ph my nutes but my meter is playing up a bit, it's at 6 when it's working, I'll grab a new one today. I've been feeding them for about a week and a half at 0.4 ec/ 150ppm. I can take another pic when I get home.

Logan Burke · Feb 18, 2019

I would totally quit feeding nutrients until we pin down a cause. Besides...most seedlings sprout with what they need to grow for the first 1-2 weeks, or at least in my own experience.

*EDIT* Meant to add, I'm not sure how prevalent things such as pythium and bad microbes are in Coco, but you may consider adding beneficial microbes to help stimulate root growth in early life and throughout their entire life.

Palmerrdgrower · Feb 18, 2019

Spirit Cloud Star Chaser said:
RH 60%
Temp 27c
Feed 1 hour after lights on and 2 hour before lights out. I don't let it completely dry out as I've read it's not good for coco but it isn't soaking. I didn't rinse or buffer my coco, supposable it had already been done (Nutriefield premium coco). I do ph my nutes but my meter is playing up a bit, it's at 6 when it's working, I'll grab a new one today. I've been feeding them for about a week and a half at 0.4 ec/ 150ppm. I can take another pic when I get home.

Is your advanced nutrients ph perfect?

Logan Burke · Feb 18, 2019

PH perfect isn't always PH perfect, keep in mind...it only is if you're following their nutrient program to the T.

Palmerrdgrower · Feb 18, 2019

Logan Burke said:
PH perfect isn't always PH perfect, keep in mind...it only is if you're following their nutrient program to the T.

From what I can gather it works best between ph 4 and 8. And if you ph it manually it will cause lock out

3rd Monkey · Feb 18, 2019

Spirit Cloud Star Chaser said:
RH 60%
Temp 27c
Feed 1 hour after lights on and 2 hour before lights out. I don't let it completely dry out as I've read it's not good for coco but it isn't soaking. I didn't rinse or buffer my coco, supposable it had already been done (Nutriefield premium coco). I do ph my nutes but my meter is playing up a bit, it's at 6 when it's working, I'll grab a new one today. I've been feeding them for about a week and a half at 0.4 ec/ 150ppm. I can take another pic when I get home.

Ph is too high. 5.5-6.0 will work, however, if you're feeding at 6.0 you are missing out on most of your micronutrients... Which is exactly what it looks like.

When your water sits, whether in a cup or medium, the ph will rise. That's called ph swing. Your runoff will be around 6.3-6.5 likely. Too high. Back her down Nute, back her down.

Logan Burke · Feb 18, 2019

Palmerrdgrower said:
From what I can gather it works best between ph 4 and 8. And if you ph it manually it will cause lock out

No cannabis plant will survive at a PH of below 5...the PH Perfect may be able to buffer the PH back to 5.8 if the PH falls to 4, or rises as high as 8, but it doesn't change the PH zone that nutrients are available at.

3rd Monkey said:
Ph is too high. 5.5-6.0 will work, however, if you're feeding at 6.0 you are missing out on most of your micronutrients... Which is exactly what it looks like.

When your water sits, whether in a cup or medium, the ph will rise. That's called ph swing. Your runoff will be around 6.3-6.5 likely. Too high. Back her down Nute, back her down.

Not true. PH does not rise when water sits. It rises for a few different reasons, most common that the plant is uptaking nutrients at a healthy rate.

3rd Monkey · Feb 18, 2019

Logan Burke said:
No cannabis plant will survive at a PH of below 5...the PH Perfect may be able to buffer the PH back to 5.8 if the PH falls to 4, or rises as high as 8, but it doesn't change the PH zone that nutrients are available at.

Not true. PH does not rise when water sits. It rises for a few different reasons, most common that the plant is uptaking nutrients at a healthy rate.

Yes it will. Try it. The carbonic acids release and evaporate, causing a more alkaline solution.

Have OP check the runoff. That'll show you what I mean.

I'm not familiar with those nutes, so maybe that has something to do with it, but I am positive it will go alkaline. TDS of the plain water will also play a role.

Logan Burke · Feb 18, 2019

There shouldn't be sitting water in the first place.

3rd Monkey · Feb 18, 2019

Logan Burke said:
There shouldn't be sitting water in the first place.

Where does it go when you water your medium?

3rd Monkey · Feb 18, 2019

That's why you hear a lot of folks say to let your water sit for 12hrs or so. Steadies the ph and then it fluctuates mostly from feeding. Easier to compensate for the swing... TDS dependent.

Spirit Cloud Star Chaser · Feb 18, 2019

Yes it is ph perfect and no I dont manually ph it because of this reason and because my pen is playing up. When I get a new ph pen tonight I'll test run off and post what it is. I have a Rec top feed set up.

3rd Monkey · Feb 18, 2019

Spirit Cloud Star Chaser said:
Yes it is ph perfect and no I dont manually ph it because of this reason and because my pen is playing up. When I get a new ph pen tonight I'll test run off and post what it is. I have a Rec top feed set up.

What for water do you use?

Spirit Cloud Star Chaser · Feb 18, 2019

I use rain water from my tank

3rd Monkey · Feb 18, 2019

Spirit Cloud Star Chaser said:
I use rain water from my tank

Should be low ppm then but you might want to check if you haven't already.

Problem with young plants

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