What am I doing wrong with the seedlings?

[Gshoo]

Hi Guys, I really have no idea what I’m doing wrong with my seedlings. Every seedling starts great in the beginning and then it gets that thinning in the base of the stem and if I don’t support it, it will break from it’s own weight. I’ve managed to save one with burrowing the damage, a member from the forum advised me to do that. But I want to understand what I’m doing wrong on the first place.
This is what I did step by step: I put the seed in distilled water for 19 hours, then I moved it on a wet paper, when the tap root was about 0.5cm I moved it into the pot. Small hole about 1cm deep, tap root pointing downwards. I sprayed the soil before potting the plant and it’s not damped off. Since then I haven’t given more water. The seedling was growing great for a couple of days with tick stem, it spent the first two days indoors until it show out of the soil. I’ve put it under my fish tank led lamp, I don’t know if it made any difference, I grow outdoors and I don’t have proper indoor setup. Then I started to take it out once it showed the sugar leaves and this thinning developed in two days. The image is from yesterday. This thing is happening with every seedling that I try to grow this year and I have no idea what I’m doing wrong.
Thanks

 

[Emilya Green]

The problem seems that it must be in something to do with your soil or your watering methods. I am curious first about the soil, and if it might be some very rich mix with lots of compost and nutrients already in it... that could easily be too much for seedlings. I am also curious if you are starting off in small solo cup sized containers with holes in the bottom for drainage, or if you have started out in a much too large sea of soil.
It doesn't seem like it could be too much or too little light... you seem to have that handled.
So that brings me to watering. You said you spray the soil before planting the seedling. This tells me that immediately upon planting the water that you applied has dropped down to the bottom of the container because of gravity, and it may have quickly gone out of the reach of the young seedling. You have not watered again, thinking that there is enough water in there (and in normal circumstances there would be) but this is a seedling and it still has not established its roots. Roots chase the water... but you have not given any more... there is nothing to chase. The plant is sitting there in the dry upper soil with no idea that there is plenty of water below it.

Instead of soaking the soil prior to planting your seedling, plant the seedling in dry or slightly moistened soil, and then water it. Water the new seedling (I like to spray them early on) with just little amounts of water, some right down the middle so that the water drops down to the bottom while showing the roots where it is going, and also with small amounts along the surface out to about 3x the present diameter of the plant. A new seedling needs to be watered in this way, twice a day until the roots establish, or in other words, until the plant has enough roots extending all the way to the bottom that it will no longer "float" or move when you water. Once the plant has found the bottom and established itself, then it is time to start properly watering and waiting for the plant to drain all the water between waterings. Seedlings need a little extra direction at first, and I suspect that this has been the major cause of your difficulties.

 

[Gshoo]

The problem seems that it must be in something to do with your soil or your watering methods. I am curious first about the soil, and if it might be some very rich mix with lots of compost and nutrients already in it... that could easily be too much for seedlings. I am also curious if you are starting off in small solo cup sized containers with holes in the bottom for drainage, or if you have started out in a much too large sea of soil.
It doesn't seem like it could be too much or too little light... you seem to have that handled.
So that brings me to watering. You said you spray the soil before planting the seedling. This tells me that immediately upon planting the water that you applied has dropped down to the bottom of the container because of gravity, and it may have quickly gone out of the reach of the young seedling. You have not watered again, thinking that there is enough water in there (and in normal circumstances there would be) but this is a seedling and it still has not established its roots. Roots chase the water... but you have not given any more... there is nothing to chase. The plant is sitting there in the dry upper soil with no idea that there is plenty of water below it.

Instead of soaking the soil prior to planting your seedling, plant the seedling in dry or slightly moistened soil, and then water it. Water the new seedling (I like to spray them early on) with just little amounts of water, some right down the middle so that the water drops down to the bottom while showing the roots where it is going, and also with small amounts along the surface out to about 3x the present diameter of the plant. A new seedling needs to be watered in this way, twice a day until the roots establish, or in other words, until the plant has enough roots extending all the way to the bottom that it will no longer "float" or move when you water. Once the plant has found the bottom and established itself, then it is time to start properly watering and waiting for the plant to drain all the water between waterings. Seedlings need a little extra direction at first, and I suspect that this has been the major cause of your difficulties.

WOW, thank you for opening my eyes. I think this is what is happening. I just didn’t see the things from the same angle. I thought that the stem is drying out, cause when I touch it with a stick, it seems firm and dry, it doesn’t look like it’s rotting. But because I read all the time to leave the plant to chase the water and I can still feel that there is water left in the bottom of the container. But the thing you said that the seedling stays in the upper dry layer and it has no roots yet to chase whatever, this totally makes sense! So last night I covered the damage with soil, that was lightly moist (the humidity from the bag) and I sprayed a couple of times in the center so some water get down the stem (that was pure intuition).
I use peat moss, sphagnum, perlite mix. The brand is BioBizz and the soil is called Light Mix. The brand says that it’s not heavily saturated with nutes. They have AllMix that is the saturated one. I use a small container with holes in the bottom. In another post you told me to uppot an auto plant as it’s up-growing it’s space, I use the same container size. If you can make an estimation from the picture below of the size (the plant you see is the one from the other thread)

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Thank you so much for your time, really helpful!