I started these seeds the day before the power outage. They were without the heat mat for 4 days on my glassed in front porch and it was very cold. We had a huge ice storm that took the power out. I thought for sure they would just freeze in the tray but just look at how good they are doing!I started some herbs and peppers Monday and will be starting tomatoes next week. SO EXCITING!I am also working on a few changes in the garden. I will show pictures when I get it finished.Enjoy your day and God bless.