Hydrogels are being used in gardens: can they kill much-needed earthworms? Will they kill unwanted pests like red ants? Are hydrogels a good thing to add to a vegtable/fruit garden?
The Gardener’s Answer
Hello, Ms. Smith in Texas: Thank you for your question. Hydrogels are water-storing granules. Sometimes referred to as moisture crystals, they are synthetic polymers. These water-storing particles are available in soluble and insoluble form. The soluble form releases the water and then is just part of the makeup of the soil until it dissolves. The insoluble is a gel form that increases in size when water is added and it continuously absorbs and releases moisture and does not break down. I am not aware of any research that proves these products to be harmful to earthworms, ants, or any other insect. There are many brands of potting soil that have these moisture crystals added to their products. In my experience, they are more beneficial when used in container gardens since they tend dry out faster than our plants that are in the ground. These hydrogels are not organic, so it is up to you whether or not to use them in your edible gardens. It is not a substitute for irrigation and mulching is always beneficial in terms of moisture retention. Just as reminder, potting soil is never recommended for use in the ground. If you want more details on the chemical make-up of these polymers you can visit http://ag.arizona.edu/yavapai/anr/hort/byg/archive/hydrogels.html