Early April, we began germinating: kale, Brussels sprouts, cabbage and okra. All started well, then the seedlings became leggy. A few days ago, I wrote about what I believed the problem was in my post, "Leggy Seedlings." I mentioned the temperature issue. One resource I listed, Purdue Horticulture, mentioned, "Most annual plants and vegetables prefer night temperatures of 60-65°F (15-18°C). Day temperatures may run about 10°F higher. If temperatures are warmer than this, leggy plants result." We never turned the heat mat off. Now, at night, the heat mat is off to simulate the temperature change that naturally occurs in nature.
After watching the three videos on seed starting from Burpee, linked below, I also determined that our seedlings needed more light. In early October, I had purchased a couple of Vktech LED grow light bulbs. I needed a grow light this winter for my aloe vera plant and citrus plant that I had to bring indoors. Our citrus plant struggled a little bit, but our aloe vera plant doubled in size this winter; I'm going to have to upgrade its pot's size as a result. Unfortunately, This grow light was not large enough to provide light for our seedlings. After some research, I decided to purchase the Hydrofarm 2-foot T5 grow light system. In addition to the temperature adjustment, it was exactly what our seedlings needed. The new seeds we planted to replace the leggy seedlings that died are standing up straight and are growing strong. Some of the seedlings from the first batch have made a come back and are now standing up staight and getting stronger each day.
It's a matter of trial and error and learning as you go. We are glad things are looking up!
To view the Burpee Seed starting videos, click the links listed below.