I've had two perfectly healthy plants both lose their all their leaves after turning brown and drying out. I've been watering them consistently. They're both new plants started from seeds about three months ago. What could be happening? Do they need repotting? More fortilizer?

I would never fertilize a sick or struggling plant. I could make things worse.

What are they?

My guess is poorly aerated potting soil plus overwatering.

What kind of plant is it?