It is a polyacrylamide polymer granule. Common brand name is ....ummm.....'Soil Moist' :-))

You might want to check on the Container Gardening forum for reviews and pros/cons of using this product. It is kind of counterproductive to the fast drainage most desirable in container gardening.

John, I would suggest avoiding using these types of products. In practice I have found that they have little effect - unless it is a negative effect. It is better to practice good watering habits. I just got done repotting a Jasmine plant that I had repotted last year, inadvertently in a Miracle Grow Moisture Control mix. It was chlorotic.

I suspect, from the amount of goo I washed out of the roots, that the mix had settled in shipping, or had been improperly mixed at the factory - maybe it was bagged out of the bottom of the bin or something. At any rate there was clearly an overabundance of "moisture crystals".

However, I had also used this MGMC in some containers for garden plants, and they did fine. Tomatoes, in particular, did well in this mix. Well, A tomato, at any rate. They didn't do any better - but they didn't do noticeably worse, either.

So while I would not purposefully buy this mix again, I will finish using it up in my outdoor containers this year. But I won't be buying any more of it. I'm a little concerned about what it might do in my compost bin as that gel breaks down.

I would not use it in anything that will be in the pot for more than a single growing season, however. Especially avoid using it in a "self-watering" container - another gadget I would recommend avoiding.