At year’s end, the University of Rostock Botanical Garden sends an updated list of the seeds collected from its cultivatied plants to over 500 gardens all over the world. The seeds are sent upon request by way of exchange. This procedure allows for genetic mixing of the inevitably small plant populations in botanical gardens in order to avoid disadvantages through inbreeding. Additionally, this system of seed exchange allows botanical gardens to easily add species to be cultivated and also to rapidly replace populations that have been lost due to pest infestation or weather damage.
To this end, throughout the year, each gardener collects seeds from his/her respective area. The seeds are then cleaned, dried, and placed in jars before they are stored in a climate chamber. All seeds are then numbered and entered into the catalog. In the climate chamber, the seeds are kept at 2 °C for a maximum of 3 to 5 years, and are examined monthly to check if they are still in good condition. Since seeds have a very different life span in storage depending on the species (in some cases only a few days, in others, many decades) and its requirements for humidity and oxygen content of the environment, only about 1000 species of the 10,000 in the garden are able to be stored in this way, and offered to other gardens.