A photosynthesis-driven crop growth model, with sub-modules for photosynthesis, leaf area development, biomass production and biomass partitioning is presented. Focus is on the application of the model for 3 practical questions:

(1) When can we expect a higher yield as a result of removing young leaves in tomato; young leaf removal will improve partitioning to the fruit, but will also reduce leaf area index and light interception

(2) how can we best mitigate the negative effects of salinity on tomato yield; salinity reduces tomato yield in at least 3 ways: reduced leaf area extension, closure of stomata and a higher fruit dry matter content

(3) what is the optimal supplementary light intensity for cut chrysanthemum? Use the model to calculate which planting densities are possible, when we increase the light intensity and accept the "standard" plant weight as optimal.