Seedlings dying off

[DKkenn]

Hi,
I june i got some coccinum flasks.
They seemed to be growing nicely, but now it seems some of them are beginning to die.
I water with fertilizer at every watering, by soaking the pots.
Sometimes i give the pots a little spray from the top.
Could the sprying have caused it, if there comes water into the shoot of the plants?

 

[Ozpaph]

That sphagnum looks old and dead. I would repot into fresh 'mix'. I would water thoroughly from the top and not sit them in water. Good air movement. Fertilizer at Nitrogen 100ppm PER week.

 

[Djthomp28]

Congrats on getting them this far! They look good.

From the look of the single seedling pot, it looks like you are having some opportunistic rot impacting your seedlings (maybe erwinia?). This is spread by splashing water. So it is likely moving from pot to pot as you water, either spraying or soaking. Also make sure you are not carrying it one your hands - wash your hands or use gloves between handle in the infected seedling. Another measure is to toss or at least isolate sick seedlings. Given their small size, saving the infected ones will be a challenge. The better goal is to keep the healthy ones healthy.

I agree @Ozpaph. Increasing the air movement and refreshing the potting mix might be in order. How dry are you allowing them to get between watering? You don't want them to be bone dry but approaching dryness with a little crunch on very top of the moss could help, especially while you get this infection under control. Finally, a cooper based fungicide might help to slow the spread if used preventatively on the healthy seedlings.

Good luck! Some loss is expected when working with flasks. How much depends on the type of orchid and the grower.