Thesis

Master's Thesis Topic: "Comparison of peat-reduced substrate mixtures (25 % vs. 12.5 % peat) in the cultivation of lettuce young plants"

Start: February/March 2026

Background:

The mining of peat contributes to climate change and has a negative impact on biodiversity in the areas where it is extracted. Peat plays an important role in the production of growing media, which is why horticulture is one of the largest consumers in Germany. Tray substrates (trays = reusable containers with multiple cells designed for raising seedlings), which are used in young plant cultivation in vegetable production, usually contain more than 70 % peat. In order to reduce the peat share in tray substrates or to be able to dispense with peat completely, different peat substitutes (compost, fibrous materials, etc.) have to be combined in such a way that the properties of the substrate resemble those of peat. This is often a challenge, as the qualities of the substitutes can vary depending on the regional availability.

The objective of this work is to experimentally evaluate the suitability of a strongly peat-reduced substrate compared to a peat-reduced substrate for the production of lettuce seedlings. The study aims to assess whether a further reduction in peat content allows comparable germination, growth, and seedling quality, and thus represents an equivalent alternative from a horticultural perspective. The substrate mixtures are based on an industrial experimental design.

Tasks:

• Investigation of quality parameters of pre-start mixtures and their components
• Investigation of seedling growth in tray substrates (greenhouse trial) 
• Performing different extraction procedures and measurements

This topic is especially relevant for students in horticultural sciences or similar studies.

The work is carried out at the Leibniz Institute of Vegetable and Ornamental Crops in Großbeeren.

If you are interested, please contact us via e-mail:

Dr. André Sradnick / Marina Larsen, Leibniz Institute of Vegetable and Ornamental Crops Großbeeren e.V., Department HORTSYS-1, Theodor-Echtermeyer-Weg 1, 14979 Großbeeren, Tel.: 033701 78362, sradnick@igzev.de / larsen@igzev.de

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