Seedling in red solo cup pleade help

[Blickmorant]

How often should I water my plants they are day 3 of seedling stage ?
They are in red solo cups

 

[Imzzaudae]

Let the medium dry out quite dry. Then give the plant enough water to dampen the soil. Don't soak it.
Let the soil dry again. over and over.

If your medium is already quite wet, let it dry, don't water again until quite dry. Then dampen.
Give it a little water then 5 min. If it needs a little more ok but keep them more on the dry side than wet.
Try and water every 3 or 4 days.