I've never used a
store-bought auto-watering system for starting seeds, but like Karen, I've used capillary matting (well, cotton flannel) under seedling trays (inserts or propagation trays).
https://garden.org/ideas/view/...
I like the idea of "bottomless" cells. I think I'll punch larger holes or slits into the seedling cells in the future. That assures good contact between the soil mix and the absorbent pad.
This pad-in-the-tray method doesn't provide auto-watering for a week away from the seeds, but it makes it very easy to keep the mix always-moist but never-soggy.
I have seen home-made designs where the absorbent mat and the seedling tray sit on something an inch or two
above the water-tray. The pad dangles from the elevated level down to the tray or water reservoir. Now the seedlings will be watered as fast as the capillary attraction of the mat and soil-less mix can pull water UP from the tray.
http://www.gardeningchannel.co...
or
http://www.burpee.com/gardenin...
Hah! Here's another system I never thought of. Plug the hole in a terracotta pot. Fill with water. Set it on top of a wicking mat in a tray. The seeds will be watered as fast as water can
soak THROUGH a clay pot.
https://deepgreenpermaculture....
