Marine macroalgae cultivation predominantly depends on plant-based material from natural waters of the sea and vegetative methods from previous harvests as well. However, this prevalent method poses drawbacks, including physiological variations within the seed stock and a decrease in genetic diversity, resulting in diminished growth rates and other by-products of cultivated seaweeds. Addressing these limitations is crucial, necessitating the developing of a sustainable and scalable approach to generate high-quality plantlets within the seaweed cultivation community and research teams. Recent strides in tissue culture and micropropagation techniques offer promising solutions, enhancing seed supply and facilitating the efficient cultivation of uniform seedlings. Diverse seaweed species have succeeded in culture and regenerating into new plantlets through techniques like protoplast, callus, and regeneration. Among various cultivation methods, vegetative and spore-based methods are considered the conventional ones. While vegetative fragments have proven their efficiency for species such as Kappaphycus, Gracilaria, Gelidiella, and Gelidium, challenges include significant seed material consumption and reduced vigor across successive generations. Conversely, reproductive cells have demonstrated utility for species with robust reproductive potential, such as Pyropia, Ulva, Saccharina, and Undaria. This chapter will discuss possible ways to increase the reproductive rate and sporulation through the natural life cycle by manipulation of abiotic factors. Nonetheless, optimization of these conditions requires extensive experimentation due to species-specific requirements, variations in plant age, and physiological backgrounds.