Challenges Facing the BNG Market
As highlighted in the Farmers Weekly article, setting up a Biodiversity Net Gain (BNG) enterprise can be a significant financial undertaking. John advises that careful budgeting and regular financial reviews are essential, as inflation is likely to erode returns over the 30-year duration of the agreement.
Establishing the habitat bank at Chalksole Farm is expected to cost around £250,000 - excluding ongoing maintenance. Key expenses include 30 years of local council monitoring fees, compliance monitoring by Biodiverse Consulting, the development of a habitat management and monitoring plan, soil testing, and legal fees associated with the Section 106 agreement. Additional costs cover the BNG register fee, allocation fees per unit transfer, and a range of planting and landscape costs such as high-quality native wildflower seed (£65,000), 260 trees with guards, nine-species hedging, pond creation (£7,000–£9,000), and site preparation (£45,000). Broker fees on unit sales typically range from 2–10%.
A key advantage at Chalksole is John’s extensive experience through JN Gardening, which provides a deep understanding of ground care and long-term habitat management -crucial to ensuring the habitat bank not only survives but thrives. The knowledge of what to plant and when is significant for this project. So far, we have already spread and rolled 1500t of chalk to assist in the establishment of calcareous grassland. Given the high costs, we would recommend a minimum site size of 20 to 25 hectares to make BNG viable.
John also advises caution in planning: avoid over-promising or aiming too high in your initial biodiversity targets. Instead, start with lower baselines, as these must legally be met. Exceeding them later results in positive outcomes, creating more units, whereas failing to meet overambitious targets can be costly. For example, the Habitat Management and Monitoring Plan (HMMP) can be strict on its requirements. For example, the conditions of a like-for-like replacement; if a five-year-old tree is lost, it must be replaced with another five-year-old tree. At Chalksole, our practical knowledge has already been applied through the use of stronger tree whips, helping improve establishment success and reduce early losses. Currently, there is limited insurance cover available for BNG habitat failure or disaster, making robust planning and management even more critical.
However, all is not lost. Despite the financial and logistical challenges, there is a growing network of dedicated professionals driving the BNG agenda forward. Experts such as Vicki Mordue from Biodiverse Consulting and Dan Turson from Natural England are just two of many who are passionate about the success of BNG and are working tirelessly to support landowners, developers, and policymakers alike. With the right expertise, planning, and collaboration, BNG can deliver long-term environmental and economic value - and projects like Chalksole Farm are helping to pave the way.
