Abstract Polycaprolactone (PCL) is a biodegradable synthetic polymer derived from petroleum that can be broken down by microorganisms. Due to its low melting point, it is suitable for composting. PCL has various applications, including in medicine and agriculture. This study investigates whether PCL degradation in compost affects seed germination. The study tested the effect of PCL extracts from compost with different temperatures and concentrations on the germination of seeds from four edible plant species: cress, lettuce, mustard, and rocket. The results showed that at low temperatures and low PCL concentrations, there was no effect on seed germination. However, at higher temperatures (55°C) and higher PCL concentrations (10% and 5%), there was a signiIicant negative effect on seed germination, with no germination in 10% PCL treatments and only 53.3% germination in 5% PCL treatments. This inhibition was observed across all plant species. The study concludes that high temperatures and high PCL concentrations in compost can negatively impact seed germination.