That description is exactly what I was thinking, especially since it’s happening with peppers, tomatoes, and sometimes cucumbers. What you’re seeing is called damping off. It’s a fungal disease that shows up when soil stays too cold and too wet before roots are fully established. Seedlings often look strong at first, then the base of the stem thins out and the plant collapses almost overnight. A few ways to work around it: - Keep the environment a little warmer and slightly drier - Make sure containers have good drainage and aren’t staying soggy - Bottom water when possible instead of watering from above - Use a seedling heat mat if you can’t control ambient air temperature — these make a huge difference - Start with clean pots and trays — damping off lives in old soil and residue, so washing containers between uses really helps reduce the risk Tomatoes and peppers are especially sensitive to this early on, and cucumbers can be a little finicky too. The good news with cucumbers is that they germinate quickly and establish fast, so restarting them is usually less painful than restarting peppers. The fact that your seedlings are getting to 3–4 inches tells me you’re doing a lot right — this is about dialing in early conditions, not doing anything wrong. If you want to go deeper on this we can dive into it during our live on Mondays as well!