The study was to provide information on changes in humidity during short-term storage of seedlings on shelves in containers covered with different materials. Collected results made it possible to specify how the type of material of loading space coverings influences changes in the interior humidity. This made it possible to determine the effect of this factor on quality of seedling material under the specific conditions produced under the covering. Analyses in the loading space were conducted using temperature and humidity sensors by Vaisala, recording humidity changes for conditions found under the covering. Sensors were placed under different levels in the loading space. Some of them were equipped with fans enforcing air circulation, facilitating measurements of humidity over a larger space. Using a KNE Data Logger measurements were registered and the results were recorded on a PCMCIA memory card. Measurements were taken over a 24-hour period, facilitating analyses of the effect of a direct action of external conditions during the day and night on changes in humidity in containers covered with coverings made from different materials. It results from the conducted analyses that humidity changes occurred in each of the measurement points. These changes were more marked during intensive operation of sunlight, when a distinct drop in humidity was observed under loading space coverings. It was stated that the material, from which rack coverings were made, has a significant effect on the course of changes in interior humidity, which could have a significant effect on the quality of stored seedlings.

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