Help, seedling are dying for the second time!

Hello, here is my setup
Strain: Blue cookie
Room: 4x3 tent
Light :Led 300w
Soil :Coco coir+pumice in 1gal pot (yes its big)
Water: distilled water 75F
Room temp: 75F-78.5F
Rh: stable at 58%

My 5 days old seedling are showing some distress
I need help figuring out what is the problem
Started using b-52 2ml/4l after the frist two leaves.
Look smaller than the last grow at 5days old with the same strain.

Here is some photo today the second after watering.

Need some advice, i dont know what is wrong.

What’s ph of the water? Also I dome new seedlings

The ph is 6.8
I could try dome but this does not look like a humidity issue right?
I use this thing to stabilise rh at 58%

I was just telling another guy I don't know how to start seeds in coco. I read about coco but never did do it. Do you know about buffering coco? Did you do that before planting? Is it the same brand of coco as last time? How's it doing today?

I just took some better pics
I always did the same with the same coco coir brand
The only difference in my setup is the pumice
Had perlite before and the frabric pot is new also

Never had problem with coco before

Deified said:

I just took some better pics
I always did the same with the same coco coir brand
The only difference in my setup is the pumice
Had perlite before and the frabric pot is new also

Never had problem with coco before

Click to expand...

So it's related to the pH problem mentioned. I think look up buffering coco.

It looks a little better today?

5.9 is the ideal feed ph for feeding in coco. Straight water is pretty much death in coco and 6.8 ph is the nail in the coffin.

eastcoastled said:

5.9 is the ideal feed ph for feeding in coco. Straight water is pretty much death in coco and 6.8 ph is the nail in the coffin.

Click to expand...

so @eastcoastled, to set it up do you want 5.9 in and keep flushing until 5.9 out too? I believe that's buffering.

I say 6.8 because my ph meter say 6.8 but the bottle of distilled water says otherwise
Distilled water has a ph of 5.8 so i should be perfect with ph
I guess my amazon ph meter is wrong.

Deified said:

I say 6.8 because my ph meter say 6.8 but the bottle of distilled water says otherwise
Distilled water has a ph of 5.8 so i should be perfect with ph
I guess my amazon ph meter is wrong.

Click to expand...

Stick it in a glass of milk to check ........... ph 6.6

Yea the meter is bad so the water has a ph of 5.8 since day1

raggyb said:

so @eastcoastled, to set it up do you want 5.9 in and keep flushing until 5.9 out too? I believe that's buffering.

Click to expand...

I haver never checked my runoff. i Usually precharge the coco at 5.8, then feed at 5.9. I don’t start seedlings in coco though, it’s not consistent no matter what brand you buy. Mine are in plugs for at least two weeks to establish a basic root system Before I shock them with coco.

raggyb said:

I was just telling another guy I don't know how to start seeds in coco. I read about coco but never did do it. Do you know about buffering coco? Did you do that before planting? Is it the same brand of coco as last time? How's it doing today?

Click to expand...

eastcoastled said:

I haver never checked my runoff. i Usually precharge the coco at 5.8, then feed at 5.9. I don’t start seedlings in coco though, it’s not consistent no matter what brand you buy. Mine are in plugs for at least two weeks to establish a basic root system Before I shock them with coco.

Click to expand...

I started my germed seeds in coco and a little perlite. The only issue I had was that one of the tops when sprouting fell off because I think it may have snagged on some perlite. Kept it moist but not wet under a seed propagator, did not have to buffer as was pre buffered canna coco, I did not know this at the time however so may have just got lucky with seeds.

sarahJane211 said:

Stick it in a glass of milk to check ........... ph 6.6

Click to expand...

Add a 1/4 tsp of baking soda to a coffee cup of distilled water. 9.0 Ph everytime. Calibrate with that. Clean your pen with distilled water after every use. Avoid these types of self destructive behavior. Milk?? REALLY?

Look like it was ph related thanks for your advices i bought
Sensi coco grow from advanced nutirients. Fixed

Its always ph related* the ph was dropping because of the coco coir itself as ive been told