In 2025, researchers extracted superabsorbent gel from discarded diapers and tested it in sandy soil, where it showed water-retention potential similar to a commercial hydrogel

Your baby's diaper and your garden's soil have more in common than you might expect. Both need something that can hold water and let it go slowly. The gel inside a diaper is really good at that. Scientists at Lomonosov Moscow State University took that gel from used diapers, mixed it into sand, and found that one gram of it could hold 100 grams of water, nearly as much as Aquasorb, a hydrogel farmers already buy to keep soil from getting too dry. The peer-reviewed study, ‘The Potential for Reusing Superabsorbent Polymer from Baby Diapers for Water Retention in Agriculture,’ published in the journal Gels, suggests that something we throw away every day might actually help crops and gardens survive when there isn't enough water.

The trash pile is bigger than most people realize

Consider the numbers that show why this research deserves attention. The most recent official U.S. figures, from the EPA's 2018 waste data (the latest year the agency has published for this category), put disposable diaper waste at 4.1 million tons. The U.S. Environmental Protection Agency found nothing significant in the recycling or composting of disposable diapers that year. Globally, the picture is worse: the Moscow State team points to about 2.4 million tons of superabsorbent polymer, the water-absorbing material inside every diaper, that are wasted worldwide each year, and the superabsorbent polymer itself is not biodegradable.


What the lab actually measured, not just claimed

This is where the study gets its credibility. Rather than simply assuming the diaper gel would work as a soil additive, Kamilla Shishkhanova and Olga Philippova's team put it to the test, extracting gel particles from three types of diapers and comparing them against Aquasorb, placed inside sand, the soil type that dries out quickest and therefore needs the most help retaining moisture. The results: the diaper gel, constrained within sand pores, absorbed about 100 g of water per gram of dry substance, roughly matching Aquasorb under similar conditions. Just 0.3% gel by volume was enough to increase the moisture range available to plant roots three to four times, and the diaper gel expanded faster than the commercial one. To see whether this research would affect plant growth, the team planted mustard seeds in sand with added gel. Seed germination and growth showed no notable differences between the samples.

Why a Gen Z or millennial gardener should care

The concept of using superabsorbent hydrogels in agriculture isn't novel. A separate study in Science of the Total Environment on leafy vegetables found hydrogel application reduced the need for watering by over 60%, saving around 196,000 liters of irrigation water per crop cycle per hectare. This time, the innovation lies in the hydrogel's source rather than the concept itself. Rather than produce new polymers for every bag of hydrogel used in gardening, the raw material may already exist in discarded diapers headed for waste facilities, though collecting and processing it at scale isn't as simple as it sounds.

The part that keeps this from being a miracle fix

This doesn't mean you should spread used diapers in your vegetable garden next weekend. Extracting the gel takes time and money because you have to sterilize it, separate it from the absorbent pulp, and wash it. The authors at Moscow State University are clear that hygiene, recovery costs, and legislative obstacles can slow wider use of this technology. Finally, this was an experimental laboratory study, with sand as the soil substitute and mustard as the sole crop tested.

What comes next

A certain type of gel derived from diapers resembles a commercial product used for plant growing. In this lab comparison, it performed comparably to its commercial counterpart at retaining water. The remaining hurdles are practical: producing the gel cheaply enough for wide use, and clearing the regulatory path that would let it move from waste stream to farm or garden. However, science shows that the diaper-derived gel has potential, even though we are not yet ready to use it.