sargassum sp reproduce with spores and fragmentation. kl for cultivation should be with fragmentation.

Both the ways are possible. If it is through sporulation, the advantage is plenty of germlings can be got, though the initial growth rate is slow. Sargassum has advantage over others in that during off season, the main foliage will be withered & lost, but there will be the stump remaining, & the plant will again grow from this stump when conditions are optimal. A plant will have stumps for only 3 times, after which everything will wither away.

Both methods are possible to culture sargassum species. If you want huge amount of sargassum in certain period.... vegitative methods is good for that. otherwise any experiment means spores methods is good

Try using nets with thallus, later, try monoline rope