Six crops with chrysanthemum “Baltica” in a greenhouse equipped with active dehumidification, full LED assimilation lighting and insect mesh have provided insight for growing a perfect chrysanthemum with less energy input. The growth was followed intensively with frequent sampling and at the end of the cultivation the quality was objectified with a perfection score. There was no flowering delay under LED. In winter, growth was insufficient, which led to branches that were too light. Moisture level could be controlled with the active dehumidification. Insect mesh in the air windows combined with high pressure mist and forced ventilation ensured a summer climate that was controlled within a desired range. The crops in autumn and spring have shown that growing under 100% LED can give good results.