A few years ago my mom had given us a small greenhouse--a small metal shelf unit with a plastic sheeting cover. It was mostly unused and we discussed whether or not another layer of protection would help things along but none of our gutter planters would fit in this small space. For Christmas Nikole gave me a small heat mat and a seed starting kit that contained a seed starting tray with 72 little plastic cells. On Christmas day we filled the tray with kale seeds. By the time they sprouted we were heating the greenhouse at night.
We left the tray of seedlings on the mat longer waiting for them to get a little bigger and then began slowly transplanting a few of them once they had a couple true leaves. I picked six of the biggest seedlings to transplant into a rectangular planter. A few days later they looked to be doing all right but they were still the same size as when I took them off the heat. Some off the ones that were still on heat were now bigger than the first ones transplanted. They are all transplanted now with some variety in sizes. But the second group planted are still the largest.
I think there are a couple possible reasons for this. It could be that the transplanting caused some shock to the system that allowed the others to grow larger and they in turn experienced the same shock when they were transplanted. The second explanation could be that there is some magic point when they should come off the heat allowing for the greatest benefit. The first bunch may have come off too early which is why the second bunch is still larger.
Now comes part two of the experiment. Learning about what container is the best for kale. Some of the transplants went into round pots, some into rectangular planters and some into gutters. I am suspicious that the gutters will not provide enough area for root growth and if they appear to struggle they might need to be transplanted into something bigger. This is what we have so far:
4 nine inch diameter self watering pots with 4 plants in each pot
1 seven inch diameter conventional pot with 3 plants
1 nine inch diameter conventional pot with 4 plants
4 6X28 inch self watering plants with 6 plants in each planter
2 48' gutters with 11 plants in each planter
2 salad bowls which will eventually have an assortment of greens but right now have three kale plants in the center.
A couple of pictures: