Overwatered – are they going to die instantly?

Coco/perlite.

I am still getting use to checking the weight of red cups. It’s been 3 days and I figured they seemed a little light.

Started filling the bottom cups until I made it around to the cups on the left side and noticed they had water sitting in the bottom cup ( I top watered last time).

Also noticed some slight fuzz growing on top layer.

After about 10 minutes I dumped the cups that I filled.

Is this dangerous? Anything I can do?

Increase VPD?

This would’ve been the 3rd watering since up potting into red cups.