Question to the Department for Environment, Food and Rural Affairs:

To ask His Majesty's Government what assessment they have made of the environmental impacts from including saponins, phosphorous peroxide, and other substances which are irritants or otherwise harmful to worms and other soil organisms, in products labelled as "soil conditioners" or "anti-worm caster"; and what guidance they have issued about the legality of doing so.

No assessment has been made. The Environment Agency assesses the presence of many chemicals in the environment, but has very limited data for chemicals in soil and the potential impacts on individual species. Saponins are a very broad and diverse group of compounds with biosurfactant and biopesticide properties and with many applications including some personal care products. The Environment Agency has developed a Prioritisation and Early Warning System for chemicals of emerging concern to systematically consider this challenge and to integrate horizon scanning with environmental monitoring and international collaboration. Substances can be added for future assessment, depending on the availability of evidence.

The Government recognises how vital healthy soil is for food production, water regulation, biodiversity, carbon storage and providing diverse habitats and agricultural opportunities. Earthworms are an excellent indicator of soil health, as they are impacted by pH, waterlogging, compaction, tillage, rotation and organic matter management.

Pesticides are strictly regulated because of their potential impacts on human health and the environment (including impacts on earthworms and soil micro-organisms) and, if authorised, are subject to conditions to ensure safe use. For many products, professional use only by properly trained operatives is one of those conditions. There are no plant protection products that are currently authorised for the control of worm casts on turf.

A consultation and call for evidence on a new fertiliser regulatory framework is planned for early 2024. The process of regulation development will be iterative as more research is needed into newer fertiliser types before requirements for these products can be drafted into law. Soil conditioners may be subject to regulation under the future revised framework for fertilisers.