The AeroGarden is one of the most popular products in the counter-top hydroponics market. While the company does offer complete pod kits that come with everything you need to start new plants, there are more economic options.
The sponges that AeroGarden sells for its own products are made from Canadian Sphagnum Peat. Peat is usually recovered from wetland areas using a special vacuum, and in Canada most of it comes from the province of Quebec. The material itself was produced as part of a process that took thousands of years, and involved plant materials being submerged underwater and very slowly breaking down.
According to this scholarly article, “The most important environmental issue in the harvesting of peat is the runoff, released from harvesting areas. Drainage mainly causes changes in regional hydrology and quality of surface waters. The leaching of phosphorus and nitrogen causes eutrophication problems into the watercourses and decomposing organic matter consumes their oxygen reserve.”
This article goes into the environmental impact in more detail.
The good news is there are alternatives, the most common being coco coir. Coco coir is produced as a bi-product when coconut husks are processed for the extraction of the long fibers from the husk. A special grade of this dust is washed, screened and graded for various uses in the horticultural and agriculture industry – including the manufacture of AeroGarden Sponge alternatives such as those made by Urban Leaf. These coco-coir alternatives are the same size as the AeroGarden peat ones, they come with a small divot at one end for placing seeds, and are also more cost-effective.