Seedling problems advice please

I have 3 feminized photoperiod seedlings dinafem critical Kush inside under a t5 grow light. They will be 3 weeks out of the dirt tomorrow and they are not looking very good to me.

Germination went good 3 for 3 popped and looked good for the first week then the first set of leaves appears to be twisty, then recently the last 7 days or so they are starting to yellow and growth generally has been very slow compared to my previous grows.

I started the plants in coco pucks and after a 2 week I moved them to solo cups of promix hp hoping to spur them along but they appear to be looking worse by the day.

In the past(3 seasons)with seedlings I have just used straight water in a sterile medium For the first few weeks and had success.

The most recent watering for these plants (yesterday) I put small dose of biothrive grow and calmag.

I try to let them dry out as much as I can between watering the temps are between 18-26 Celsius between day and night usually around 22 and it’s 18 on 4 off for light. Not sure on humidity.

I am at a loss and was hoping someone on here has an idea. I have had really good success the last 3 years starting from seed doing both photo periods and autoflower using these methods can someone help me
And see where I might have gone wrong?

I have included some pics

Thanks

Elkhorn said:

I try to let them dry out as much as I can between watering the temps are between 18-26 Celsius between day and night usually around 22 and it’s 18 on 4 off for light. Not sure on humidity.

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A bit more specific here...since in that solo cup a week ago..how many times have you watered and how much water? What is your source of water? What ph?
Temperature wise..you're saying at night it's 22?..but in the day it can shift 8 degrees? So at times it may be cooler in the day than at night? Where exactly is the thermometer in relation to the cups? How far is your light? Humidity is important to know...and i say this because i see your pepper plants behind cupping as well at the top. Do you have a fan circulating air?

Almost looks to me like the light is to close??

Blitz35 said:

A bit more specific here...since in that solo cup a week ago..how many times have you watered and how much water? What is your source of water? What ph?
Temperature wise..you're saying at night it's 22?..but in the day it can shift 8 degrees? So at times it may be cooler in the day than at night? Where exactly is the thermometer in relation to the cups? How far is your light? Humidity is important to know...and i say this because i see your pepper plants behind cupping as well at the top. Do you have a fan circulating air?

Click to expand...

It was transplanted from just a coco pod to inside solo cup one week ago it was watered at transplant and one more time a week later which was yesterday. The water comes from a well and it had a ph of 6.5. I didn’t need to water it yesterday(wasn’t super dry) but I wanted to get some nutes into the medium.

The plants schedule is 18 hours day 6 night my bad in the op. I have seen temps as high as 26 Celsius during the day period and as low as 18 at the night period but usually at night it’s 20.

The thermometer is just an egg shaped digital that sits beside the solo cups in the bottom of the grow box.

My light is 2” above the plant it is not hot to my hand at the canopy, I can look into both a fan and humidity gage tomorrow.

I grew an auto with them it was so robust under the same conditions it’s already been topped and gone out to the greenhouse.

I'd say slight over-watering. They shouldn't need much nutes yet. Some light air movement will help the medium dry out if the plants aren't drinking enough.