The invention relates to a method for controlling the atmosphere in a closable space filled with agricultural or horticultural products. The method comprises directly detecting the respiration of the agricultural or horticultural products and adjusting an oxygen content, a carbon dioxide content and/or a nitrogen content in the space subject to the detected respiration. The respiration is detected here periodically, in each case for a determined time, and the space is sealed off from external influences during detection of the respiration. A very good control is achieved by taking the actual respiration as starting point, and a highly reliable detection forms the basis of this control when the detection is performed periodically for some time in a completely isolated atmosphere. The invention also relates to an installation for performing the method, and to a closable space provided with such an installation.