Seedling stopped growing

Hi guys, I am again posting a question here because my plants are dying again haha.
So, I planted two White Widow seeds a few weeks ago, I let them germinate and then I transferred them in coir to make the seedling grow.
I first used a 300W light for both plants, now I use two 300W lights for the two plants.
At first the plants grew pretty good, but at a certain point one of the plants stopped growing and became a bit yellow and the leaves seem dead and dry. The other plant grew substantially more but it seems like the leaves are turning yellow as well.
The lights are at 60 cm above the plants, the temperature is always between 23 and 26 degrees Celsius, and the humidity is always around 55%.
Wat could cause the plants to die. Is it too much water? Or too much light? I really do not know, and I hope you can help me.

Wait for confirmation. But you need to give them a quater strength feed as choice is inert and needs food for them to grow

Again wait for confirmation. But did you wash the choice first? This may be a problem.
What size pots are they in
Can you turn the lights down at all and how close are they to the seedlings. 300w should do both plants for light

go go kid said:

Wait for confirmation. But you need to give them a quater strength feed as choice is inert and needs food for them to grow

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I didn’t understand the quantities you described but I gave my plants a little bit of nutrients a few days ago

go go kid said:

Again wait for confirmation. But did you wash the choice first? This may be a problem.
What size pots are they in
Can you turn the lights down at all and how close are they to the seedlings. 300w should do both plants for light

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I didn’t wash the coir. And the light are at 60 cm from the plants

Ok. I don't know the medium you grow in. So wait for someone who does

go go kid said:

Ok. I don't know the medium you grow in. So wait for someone who does

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I forgot to mention that only a little part of the soil is coir, the rest is normal soil i bought from the store

My-Private-Stuff said:

I forgot to mention that only a little part of the soil is coir, the rest is normal soil i bought from the store

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So you're growing in soil.

What type of soil was it? Potting compost or other?
You don't need to feed for about 4 weeks or so. You've probably over felted your plants so only give water from now on until you start to see yellowing or the larger fan leaves. So no food for 4 weeks.

What size pots you got them in. You only need solo cups for 2 weeks and then transplant to the larger pots

Looks like soil. Should start seedlings in small pots. More than likely overwatered and possibly overfed if the soil has starter nutrients.

MickFoster said:

So you're growing in soil.

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Yes, but I don't know if the seedlings are already in contact with it

go go kid said:

What type of soil was it? Potting compost or other?
You don't need to feed for about 4 weeks or so. You've probably over felted your plants so only give water from now on until you start to see yellowing or the larger fan leaves. So no food for 4 weeks.

What size pots you got them in. You only need solo cups for 2 weeks and then transplant to the larger pots

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They where in solo cups for about 20 days and then I transfered them in normal soil, I don't know exactly what soil it is

go go kid said:

What type of soil was it? Potting compost or other?
You don't need to feed for about 4 weeks or so. You've probably over felted your plants so only give water from now on until you start to see yellowing or the larger fan leaves. So no food for 4 weeks.

What size pots you got them in. You only need solo cups for 2 weeks and then transplant to the larger pots

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I fed them only once because I saw that they were dying. But since then I didn't give anyting, also no water because the soil seems still humid

twentyeight.threefive said:

Looks like soil. Should start seedlings in small pots. More than likely overwatered and possibly overfed if the soil has starter nutrients.

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Okay, I don't think I overfed them, becuase I gave only once nutrients, but maybe too much water, does it look like that?

Those aren't plants, they're tiny little seedlings. And you have 2-300 watt lights on them? I take it they are led as well? Why not start them on a T-5 fluorescent light until they can handle the bigger lights? I think you fried them with too much light, just to begin with.

Flork said:

Those aren't plants, they're tiny little seedlings. And you have 2-300 watt lights on them? I take it they are led as well? Why not start them on a T-5 fluorescent light until they can handle the bigger lights? I think you fried them with too much light, just to begin with.

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couldn't I just move the lights farther away?

My-Private-Stuff said:

couldn't I just move the lights farther away?

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Yes. You don’t know what soil you’re in? they won’t do much for awhile you put little ladies in big pots they’re growing roots atm. Just be patient. not knowing what soil you’re using is not a good thing. You could end up over feeding them if the soil is already hot.

Lordhooha said:

Yes. You don’t know what soil you’re in? they won’t do much for awhile you put little ladies in big pots they’re growing roots atm. Just be patient. not knowing what soil you’re using is not a good thing. You could end up over feeding them if the soil is already hot.

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I'll inquire about what kind of soil it is.
But do you really think that they are coming back? Because, at least the little one, seems like it's gonna die really soon.

My-Private-Stuff said:

I'll inquire about what kind of soil it is.
But do you really think that they are coming back? Because, at least the little one, seems like it's gonna die really soon.

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The smaller one is dead but the other looks like it may make it

My-Private-Stuff said:

They where in solo cups for about 20 days and then I transfered them in normal soil, I don't know exactly what soil it is

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If those are over 20 days old you have some other problem.