Yes; it's magic!

When you thin of it, hydroponics in general is about as close to real magic as it gets!

I make my own grow plugs (when I'm starting from seed) using a small tuft of fiberglass wall insulation stuffed into a plastic 72-cell propagation tray sitting in a little puddle of nutrient at the proper EC and pH!

I think there are some pictures of that somewhere on my Web page (URL in my profile, if you're interested).

According to General Hydroponics (Rapid Rooters), theirs is bonded by a plant derived polymer. That's the extent of what it says, though.

Excellent question hydroangel!

I believe latex is used as a binding agent. Using corn starch sounds interesting though! Be sure to share some pictures when you can.

Once you have the process streamlined consider experimenting with additives like rooting hormones (indole-3-butyric acid) or beneficial fungi. Just remember to add them after you microwave, not before ;)

I saw your comment on making coir plugs back in (2009), are you still using the cornstarch or have you found a better solution. I'm a bit worried that cornstarch might break down and clog up the pump in my hydroponic kit

Peat moss bound with gelatin works well, if the plugs are small you can place them in a piece of cotton finger bandage to prevent anything loose getting into the reservoir. Gelatin has a high nitrogen value which is useful to the seedlings. Cornstarch may attract mold and its not flexible like gelatin once its set

This is exactly a problem I am trying to solve today. I 'll try with cornstarch, but first will make a paste of it, brewing it with water. Then add to coco coir and mix.

Some feedback from you guys would be appreciated. Any photos? Any success?

Plant based polymer

im going to try mixing mine with agar agar