Changes in chlorophyll and carotenoid levels can be used to monitor responses to nutritional interventions and alert to progressive changes in plant health. Following extensive growth and fruit bearing, leaf pigment concentrations dropped. To restore the energy efficiency of the Centenary leaves, a liquid feed (N:P:K 8:34:32) was applied in weeks 22, 23 and 24. The figure above shows a marked increase in chlorophyll concentration by week 25. A similar response is seen in week 30 following further nutrient application in week 29.