discussed. A finite element inverse technique using a photosynthetic algorithm (PA) is described, fol- lowedbyacomparisonofneuralnetworktrainingby a photosynthetic algorithm versus a genetic algo- rithm (GA). Leaf cellular automata (LCA) are intro- duced, and their application to optimization problems is discussed. Second, a decision system consisting of neural net- works (NNs) and GAs is applied to the optimization of plantgrowthunderhydroponicsinJapaneseplantfac- tories. In this system, plant growth as affected by the nutrient concentration is first identified using NNs, and then the optimal l-step set points of the nutrient concentration that maximize the plant growth are de- termined through simulation of the identified NN model using GAs.