A new study published in Nature Climate Change highlights the important role plant nutrients play in carbon retention within forests. Whilst it has been widely accepted that climate and the amount of CO2 in the atmosphere control the productivity of forests. It now turns out that without adequate levels of nitrogen, phosphorus and potassium the potential carbon storage of a forest is limited. Whilst to many gardeners this may seem logical, after all good fertilizer is key to bumper vegetable crops, what this means is that many of our state-of-the-art Earth system models are lacking an important component.