I've been growing veggies and flowers by starting the seeds indoors for a few years now, but this year, the seedlings never really got big enough for transplanting. Eventually I had to transplant, but many of them died after transplanting, as they just weren't very strong. I don't know what I did wrong this year. They had light, bottom heat, and shelter. I gave them light and heat for ~14 hours a day. This year I moved them from the garage into the house- is it possible they needed colder nights? I didn't fertilize, I admit, but I didn't in previous years either. Any suggestions would be welcome, so I don't make the same mistake next year.
My Seedlings Didn’t Really Grow
Certified GKH Gardening Expert
It sounds like they had enough light and heat, so water would be the likely culprit. Potting and seed starting soil is normally high in peat. Peat can dry out and actually start to repel water when you water, so while you think you are adding water, only the top part may be getting wet. The lower part stays dry and the roots just don't develop right.
You can prevent this by making sure that you keep your seedling soil damp at all times and don't let it dry out completely. If you do accidentally let this happen, soaking the tray in a tub of water for a bit will force the peat to rehydrate and start taking water again.