Growth has slowed.

Ok I’m looking for opinions. I’ve got three or four true leaves on my seedlings. Which are setting and doing well in an east window. The growth rate has dramatically slowed. Am pondering adding a heat mat to warm the soil and lighting for length and intensity. Ideas appreciated.

I would add the light before the heat. Without the light the heat may not work as well.

As long as the seedlings are doing well, there are advantages to having slower growth, in that the seedlings can sometimes get too large for your indoor plant area, before its warm enough to move them outside.