A survey taken of the water flowing out of three Hampshire farms belonging to The Watercress Company has confirmed that the business is positively enhancing the biodiversity of the water that runs through its beds and into the River Itchen.

Robert Aquilina, the independent consultant ecologist who undertakes the survey every six months on behalf of The Watercress Company stated: “The key finding of the survey is that biodiversity has increased across all three sites, reflecting ongoing consistently very good water quality, allowing a very good range of aquatic invertebrates to thrive.”

The range of highly beneficial macroinvertebrates that are found in the watercress beds and the streams that leave the watercress beds include flatworms, various species of snails, pea mussels, leeches, stonefly, caddis, various types of ramshorn, water cricket, water boatmen and many others.

In the last survey a rare moss beetle was discovered that had never been seen in the south of the UK, but which was thought to have found refuge in the chalk streams of Hampshire with a constant temperature of 10˚c as the water leaves the watercress beds. Mr Aquilina explained that adult moss beetles tend to peak in May and so he had not been expecting to find them in the autumn. Instead, he had witnessed many other types of beetles, amongst them crawling water beetles, diving beetles, riffle beetles, marsh beetles and scavenger water beetles.

The Watercress Company is the UK’s biggest grower of watercress with 50 acres of watercress beds split between Hampshire and Dorset. Watercress is a unique crop with its roots clinging to the gravel base of the beds, while the plants sway in the nutrient-rich spring water as it flows past. The water is pure and clean, forced up from deep underground aquifers where, in Hampshire, it has filtered through the chalk of the South Downs. Once the water has run through the watercress beds it flows out into the River Itchen. 

Tom Amery, MD of the Watercress Company said: “We take our stewardship of the water extremely seriously. We began the twice yearly survey to support our discussions with groups like the Upper Itchen Initiative and Salmon & Trout Association to demonstrate how clean the water is leaving our farms. We are very fortunate to have been an early adopter of reduced input farming; stopping the use of pesticides on our watercress 20 years ago, we also adapted our business in 2016 to remove the use of Nitrogen and we carefully regulate the use of Phosphate, reducing its use by 90%.

“In all of these concerns we have worked closely with the Environment Agency and unlike many farms we are closely monitored and regulated. We are proud to say that we run one of the most efficient farms in the UK with super low inputs producing six crops per season of nutrient dense watercress grown in fresh flowing spring water. The watercress production system actively removes as much of the free nutrients from the water as possible which assists in reducing nutrification downstream. The range of invertebrates thriving in the outflows from our farms appears to confirm this system is proven to work.”

There are many other threats to the Itchen and Test from septic tank discharge, road wash, issues with water companies and runoff from less sustainable farming operations. The Watercress Company feels that they have demonstrated that working closely with the Environment Agency gets results and that as an organisation it can deal with the challenges posed by these concerns. 


The Government has recently included watercress in its new Geographical Indications (GI) Scheme. This provides watercress with a protected status so that only specific plants grown in flowing water can bear the name watercress when commercially sold in Great Britain. This recognises the expertise it takes to grow the crop and the care farmers take when working with the water throughout the growing process and after.

Tom Amery again: “The government has recognised us as experts in growing watercress.  Key to that is honouring the water that supplies watercress with the nutrients and minerals which makes it so healthy. It is essential we minimise any impact on the land and rivers around us and can measure our success in improving biodiversity on our farms. The regular independent surveys we commission make sure we are achieving that.”

Read the full report here or read it and all previous reports at https://www.thewatercresscompany.com/working-with-water-and-ecology