I know it is late in the year. I started my seeds around a month ago. They were doing very well! They appeared strong and had a lot of leaves. I planted them in tiny carboard pots. They were in a bright window. I sprayed them gently with a little water each day because the top soil was very dry. Overnight, they fell over. They were standing tall and strong, and the next morning they were wilted and flat. The leaves appear weak and soft. I'm not super knowledgeable, however, I assumed they were over watered. I say that not because I felt like I was over watering them, but because of their appearance. I watered them the same amount of squirts each day. The top soil was super dry on top. Could something this dramatic happen over night from that? Can I save them? I didn't water them today. They look no better tonight. This makes me so sad because we were looking so good... Thanks!

Did you water them? Or just sprinkle them? You say the soil surface was dry so your were sprinkling. But if you don't water, the soil under the surface will be dryer. You need to water until water comes out the bottom of the pot then wait until the surface is dry and water again.

agreed.
They do best with bottom water, not spraying.
Was it 'top of the soil' or topsoil, not potting mix or seed starting?
You still have plenty of time, can seed directly into the garden right now.I have loads of volunteer tomatoes coming up.

Thank you! I can't believe I didn't think of that. This is my first year with seeds. I had read an article talking about spraying the top of the soil for seeds. Maybe they just meant while sprouting, or maybe it was just bad advice. I have watered them fully. Hopefully they live! If not I will try again! :). It was just a potting mix. This was more of an experiment than anything!

Glad you didn't have your heart set on them. I've lost plenty.
There's a reason why each plant makes thousands of seeds to replace itself- funny, but think about it...
Potting mix should be fine, it's just topsoil that would be too heavy.
And probably spraying while the seeds are still not showing- keeping the soil moist to the top. I cover lightly with plastic. Shortly after you see green, bottom watering works well for me.
Onward