I start seeds i pots made from newspaper. Love the re / up cycle thing. From there, I used to go into solo cups but then I realized something. I can get almost as many 2 liter bottles into a tray as I can solo cups. After experimenting with them, I also learned that they are less prone to root rot if you leave extra water in the tray. Also, there is plenty of room to grow and to train roots to grow down. They are not nearly big enough for mature plants, but seem great for starting indoors. Just drill holes in the bottom and wrap with black duct tape to keep light off the roots.
Anyone else? What do you use?
Anyone else? What do you use?