Libyan Journal of Basic Sciences (LJBS) Vol: 17, No: 2, P:49-60, August. 2022 https://ljbs.omu.edu.ly/eISSN 2707-6261 Using spirogyra algae to enhance seedling growth of Trigonella foenum-graecum L Salmeen. H. Elhaj and Rabha. M. Mansur * Department of Botany, Faculty of Science, University of Omar Al-Mukhtar, Al- Bayda, Libya Correspondence author: Donianuri72@gmail.com Abstract Modern agricultural methods rely heavily on bio-fertilizers to enhance the production of many crops, but the extensive use of currently available inorganic and chemical fertilizers may pose a serious threat to both human health and the environment. Algae play a key role in soil fertility, it has been suggested that algae better support the taller growth of the plant in all its life stages by supplying the essential growth elements) needed for normal growth, development, photosynthesis, and reproduction. In the current study, we calculated the percentage of germination index and viability of seedlings of fenugreek plant that were grown under different conditions, where an equal number of fenugreek seeds were soaked in spirogyra algae extract (1% as biofertilizer) to see its effect on the growth of seedlings for 6 to 12 hours, likewise in sterile distilled water (as a control) for comparison. The results showed that the addition of spirogyra extract led to an increase in seed germination (93%) of the soaked seeds within 12 hours (effective treatment) compared to the other treatments. The statistical analysis showed significant differences in all measurements compared to the control group. The viability and growth index of seedlings that include photosynthetic pigment content (chlorophyll A and B and carotenoids), plant height, number of leaves, number of roots, root length, and fresh/dry weight of seeds treated with Spirogyra extract for 12 hours compared to untreated seeds. Keywords: biofertilizer; carotenoids ; spirogyra; seedling growth and Trigonella foenum-graecum L.